The detection performance of light screen array (LSA) is predominantly affected by sky background noise, and this probably leads to decrease of its effective detection height. This research addresses a method based on constant false alarm rate (CFAR) to solve this problem effectively. The characteristics of the dynamic signal of the LSA are reasonably analyzed, and a Bayesian classification model is scientifically formulated. We construct an adaptive threshold detector using CFAR, thereby extracting the dynamic signal, effectively, under the poor signal to noise ratio (-1 to 5dB). Through semi-physical simulation and live ammunition test, the assessments demonstrate the proposed method can increase the effective detection height of a flying projectile by 20% at least, and its performance is better than previous those.

For laser processing the existing great power consumption, low precision, complex circuit and so on, studied a kind of based on embedded ARM board and XY2-100 protocol high-speed galvanometer control system, integrated with the human-computer interaction interface, effectively reduce the control of the process of signal transmission attenuation, and put forward an effective inherent to laser machining distortion optimization compensation scheme and the calculation method was improved, by making the DEMO board and test the running stability of the whole system, in terms of speed, accuracy, better than the existing control system can realize more than 20000 times per second high-speed galvanometer deflection, position control accuracy, small error, has strong practical application prospect.

In order to improve the stability of the secondary mirror mounting structure and reduce the influence of the position change of the secondary mirror on the imaging quality of the camera, the secondary mirror support structure was studied. Aiming at the problems of traditional secondary mirror support, a new type of secondary mirror bracket is proposed in this paper. The finite element analysis results show that under the same obstruction ratio, the torsional stiffness, the stiffness along the optical axis and the thermodynamic properties of the new secondary mirror bracket are similar to the secondary mirror traditional support structure, but the weight of the new s bracket is only 15.2% of the traditional support structure. The new bracket solves the shortcomings of the traditional secondary mirror support structure, such as high cost, long period and heavy weight, and is easy to assemble. It has been successfully applied in the all-day star orientation instrument.

In recent years, optical detection technology for human skin has developed rapidly. This paper introduces a novel imaging technique, polarization parameters indirect microscopic imaging. We insert polarization-modulation mechanics into a conventional reflection microscopic imaging system. Instead of normal light source, we use a high transmission infrared light source. The resolution of such optical microscopy can reach to 100 nanometers. Using this imaging system, we can obtain multiple optical vector parameters such as polarization phase, degree of polarizations ,wave vector phrase, spatial angles, angles and modulation etc. By analyzing the polarization parameters, we obtain inversion images of human skin.

III V compound semiconductors, such as Indium phosphide (InP) and its doped materials, are very suitable to make the transient high power photoconductive semiconductor switches (PCSSs) with its picosecond (ps) time response. An InP PCSS is fabricated, and measured under the input voltage up to 2000 V and the optical energy up to 2000 uJ conditions. The experimental data are explained by using a simple model. It is shown that the output voltages increase initially with the increasing optical energy at the initial stage, but saturate when the optical energy is big enough. The output voltages almost increase linearly with the increasing input voltage under the low optical energy condition, but deviate slightly linear relationship when the optical energy is high. Therefore, this paper proves a light-controlled photoelectronic device which could provide stable ps-order pulse. And this device could be the power source of the ultra-fast electric product.

The AIMS, a solar telescope with a primary mirror of 1m in diameter, is designed with an off-axis Gregorian optical system and an alt-az mounting structure. The image rotation of the AIMS will be produced both due to alt-az mounting and the movement of plane mirrors system during the monitoring of the sun. Therefore, a derotator is planned to correct and compensate the image rotation to make the terminal instruments of the AIMS work properly. The image rotation in astronomical telescopes consists of the object field rotation and the image field rotations. In this paper, the rotation of the object field for the AIMS is presented and calculated. The image field rotation due to the plane mirrors system with the movement of azimuth axis and altitude axis of the AIMS is theoretically determined by using the ray tracing and vector matrix method. The relationships between the image filed rotation and the variation of the azimuth and altitude of the telescope are discussed. This work may be very helpful to evaluate the deroation methods for the AIMS and will provide an important theoretical support for precision control of the derotator to eliminate the image rotation in real time.

The polarization maintaining fiber grating (PM-FBG) can be used as a multi-parameter sensor due to the inherent birefringence. In this paper, the spectral characteristics of PM-FBG under lateral pressure are analyzed. The experimental device is set up to measure the reflection spectra of PM-FBG with different lateral pressure and loading angles. The experimental results show that the applied stress perturbation will change the intrinsic birefringence axis of the polarization maintaining fiber and change the effective refractive index of the fast and slow axis. So the PM-FBG can be used as pressure sensor by measuring the shift rate of the reflection spectra.

Spatial-spectral interference carries the spectral phase difference information between short pulses. We propose a new method of time delay retrieval via the slope of spatial-spectral interference fringe in the case of only time delay without high-order spectral phase difference between short pulses. The analytical expression is deduced based on the principle of spatial-spectral interference. The simulation results show that the slope of spatial-spectral interference fringe and the crossing angle between short pulses are both important for the calculation accuracy. This proposed method has advantages of no direction-of-time ambiguity, simple principle and calculation process, which are helpful for the measurement and control of the time delay between short pulses in coherent combination, plasma parameter diagnosis and so on.

Conventional transport-of-intensity equation (TIE) based phase imaging is performed in wide-field microscopes. In this paper, we present phase and fluorescence dual-modality imaging in a confocal laser scanning microscopy (CLSM) system. To perform phase imaging, the depth of field (DOF) of the CLSM system was extended by using a tunable acoustic gradient index of refraction (TAG) lens. Under transmitted illumination, a few intensity images of a sample at different defocusing distances were recorded. The phase image is reconstructed from these intensity images by using transport-of-intensity equation (TIE). Fluorescence image is obtained by 3D scan of the sample, providing a 3D sectioned fluorescence image. The obtained dual-modality images with pixel-to-pixel correspondence provide for the same sample complementary information (structural/functional), to extract complex biological parameters. We demonstrate the combination of the two imaging modalities enables standalone determination of the refractive index of live cells.

Endoscopic imaging technologies, such as endoscopic optical coherence tomography (OCT), near infrared (NIR) fluorescence, photoacoustic (PA), and ultrasound (US) have been used to investigate vascular and morphological changes as hallmarks of early cancer in the gastrointestinal (GI) tract. Here, we developed two multimodality imaging systems which are integrated PA/US and integrated OCT/NIR fluorescence which can obtain layered architecture and vasculature simultaneously. In vivo imaging of rectum wall from Sprague Dawley (SD) rats with these two imaging systems were demonstrated. Both imaging systems enable the use of one imaging probe for performing two different imaging, thereby improving prognosis by early detection and reducing costs. For integrated PA/US, the architectural morphology and vasculature of the rectum wall were visualized without the usage of contrast agent, but slow imaging speed and usage of match medium are the main limitations for clinical translation. With regard to the integrated OCT/NIR fluorescence, it is able to perform high speed imaging, however the addition of contrast agent and limited imaging depth are the main concern for clinical application.

With the development of the digital airborne photogrammetry technology, the more performances of the optical system for airborne mapping camera are required, such as the longer focal and the wider field of view (FOV). At the same time, the secondary spectrum correction becomes more important and difficult for the optical system design. A high performance optical system of airborne mapping camera with 200mm focus and 2ω=60° FOV is designed in this paper. The range of work wavelength is from 430nm to 885nm. A two-layer HDOE with negative dispersive characteristic is used to eliminate the secondary spectrum in the process of optical system design. The diffraction efficiency of the designed two-layer HDOE is up to 90%. From the result of design, the MTFs in whole fields are over 0.5 at 90lp/mm, which shows that the system has a great image quality. Meantime, the thermal analysis is done at the temperature range between -20°C and 40°C. As a result, MTF curves of the system at-20°C ~40°C show that a great image quality is kept, which meets the design requirements.

Microfluidic chips and microreactors have been widely used in various fields due to their low reagent consumption, fast reaction speed and good safety. Besides, temperature is the key parameter of many biochemical reactions. So it is important for the creation of temperature controllable micro-reactor. However, There are some problems in existing micro-reactors, such as structure, size, temperature control method and temperature distribution. Here we report a method based on an improved femtosecond laser wet etching technology and metal-microsolidifying process for the fabrication of microchannel and 3D microcoils inside fused silica. Based on this approach, we fabricate a temperature controllable micro-reactor used for polymerase chain reaction (PCR) by integrating 3D metallic microcoils and microfluidic channel twined by microcoils inside fused silica. We precisely and conveniently get required temperature by varying the voltage of microcoils. The micro-reactor also exhibits a high integration level and good uniformity of temperature distribution. In addition, we get a miniaturized device which can be conveniently integrated.

A novel double-clad As₂Se₃ chalcogenide photonic crystal fiber is proposed and the slow light via stimulated Brillouin scattering is theoretically investigated. The Brillouin gain spectrum by taking into account the high-order acoustic modes is analyzed. The simulated results indicate that the slow light can be tuned by varying the air filling fraction in the inner cladding. The time delay upto 1120ns can be achieved with 1-m-long fiber when pumped with 10mW. But these features of slow light are less affected with the change of the air filling fraction in the outer cladding.

The magnetic field is one of the most important physical observables with about all electromagnetic information. Larmor precession atomic magnetometers based on optical pumping experienced considerable attention recently. However, the sensitivity of this kind of atomic magnetometers is limited by their spin coherence time and the systematic noise. Here, we propose a self-sustaining atomic magnetic gradiometer that shows a superior 1/τ behavior in the magnetic field uncertainty measurement over time. The gradiometer is implemented by mixing and filtering the different frequency signals from two adjacent spin self-sustaining magnetometers with a baseline equal to 1 cm. The common-mode noise is suppressed and a gradient sensitivity of 200 fT/(√Hz=cm) is realized, being close to the shot noise limit.

In order to reasonably determine the safe speed limit of expressway under several meteorological conditions such as stagnant water, icing, snow, fog , and provide the driver with the maximum acceptable safe speed, this paper proposes a Freeway variable speed limit system based on traffic meteorological environment monitoring. This paper establishes a speed limit model based on visibility, illumination and road surface state. The STM32f103 is proposed as a controller to collect meteorological information in real time using road surface condition monitoring equipment, visibility meter and illumination meter. And use LED information board to prompt the maximum safe speed in real time. This paper is based on QT5 development of the host computer client. QT has the advantages of high modularity and good reusability, and can be extended to other functions as needed.

The angular micro-vibration of a high resolution camera mounting on an agile satellite was achieved based on pairs of liner accelerometers alignment and numerical integration method. Three pairs of sensors were mounted at different portion of the satellite for studying the structure transfer character, including the Reaction Wheel (RW)interface, the camera interface and the camera tail. The results showed that the RW original micro-vibration standard deviation (STD) output acquired at the RW interference was 1.63μrad at RW 400rpm and increased to 2.43μrad when the RW speed up to 800rpm. When transferring from RW to the camera interface, the angular vibration response STD was attenuated to 0.31μrad@400rpm and 0.27μrad@800rpm, and finally to the camera tail the angular vibration response STD became 0.31μrad@400rpm and 0.30μrad@800rpm. We can see that the satellite-camera structure has a good attenuation effect on the micro-vibration, the output angular micro-vibration STD is about 0.31μrad with an input of 1.63μrad~2.43μrad. the stiffness of the camera is pretty good, ensuring that the micro-vibration STD difference between the camera flange and the camera tail is smaller 0.03μrad. In addition, we found that the FOGs useful bandwidth wasn’t insufficient when acquiring about 340Hz main frequency vibration signal in our case, even though a higher stiffness flange was recommended which connecting the FOG and camera.

All-time atmosphere temperature measurement is important for meteorology. High spectral Rayleigh Lidar at solar blind wavelength 266 nm is proposed to avoid solar background light of daytime and realize all-time atmosphere temperature profiling measurement. At the same time the Rayleigh scattering spectral width is broader and scattering intensity is stronger for 266 nm wavelength compared with 355 nm. Two Rayleigh scattering channel signals, which determine the atmosphere temperature, are filtered with two Fabry-Perot filters (Filter-1 and Filter-2) which located on the same side of the wings of the Rayleigh-scattering spectrum. Mie signal is detected with a third Fabry-Perot etalon filter (Filter-3), which is centered at the laser frequency. The Fabry-Perot filter parameters are optimized and analyzed by numerical calculation based on 266 nm wavelength. The FWHMs of Filter-1, Filter-2, Filter-3 respectively are 185 MHZ, 1 GHz, 285 MHz and their central relative frequencies respectively are 1.6 GHz, 3.5 GHz, 0 GHz. The Mie rejection of Filter-1 Rayleigh channel is up to 45 dB. The temperature measuring sensitivity is 0.49%/K (3 km). The system transmittance, SNR and temperature error are calculated and analyzed for different ozone concentrations. The results are shown that the temperature error is less than 1 K up to a height of 5.3 km at all time under the condition of 150 mJ laser energy, 400 mm receiver telescope and 40 ppb O₃ concentration.

Microlens arrays (MLAs) with special functions such as superhydrophobicity and self-cleaning ability are highly desired in the micro-optical system which is often used in easily polluted environment. In this paper, a new method is demonstrated to fabricate the MLAs with a high fill factor and superhydrophobicity. The method combines femtosecond laser wet etching, polydimethylsiloxane (PDMS) replication and subsequently femtosecond laser direct writing process. The fabricated MLAs decorated with micro/nanoscale hierarchical structures compared with the normal MLAs. Water droplets on the as-prepared surfaces exhibit superhydrophobicity and ultralow adhesion which endows the fabricated samples possess self-cleaning property. The as-fabricated MLAs could find their applications in bioscience research, ocean exploration, endoscopic surgery, microfluidic system, etc.

When optical images are used to measure the three-dimensional position of a target, it is necessary to project a laser source onto the object, and the center position of the pupil spot should be calculated. The laser light source has high application value, because the brightness of the spot is much higher than the brightness of the environment. When the camera is in a low exposure time, the spot will be in stark contrast to the surrounding environment, which can achieve the conditions of the image measurement. The laser can be divided into point laser, line laser and cross laser according to the simple emission shape. In this paper, the center positions of these lasers are solved separately. After calculating and testing, the stability and accuracy of the cross laser can be verified. The results can provide an important source of light source selection and new ideas for image measurement.

We report the wavelength tuning of type-II “W” quantum well of interband cascade laser. By changing the thickness of the InAs electron well, the wavelength of the active region is adjusted. We found that the whole 3-4 μm spectra can be realized and the intensity was basically the same by measuring the photoluminescence (PL) of the active region. It showed that the type-II “W” quantum well of interband cascade laser can achieve 3-4 μm range without attenuation. In addition, we calculated the wavelength of quantum well of different InAs thickness by the 8-band k·p method. And we found that the wavelength of the active region varies with the thickness of the InAs electron well, which is consistent with the theory. In addition, the measured wavelength was different from the theoretical wavelength, which may be due to the As incorporation. The incorporation of As into the InGaSb layer will lead to blue shift in the wavelength.

We report on successful fabricating of GaSb-based type-I quantum well distributed Bragg reflector (DBR) lasers emitting at 2080nm. Second-order Bragg gratings of chromium were patterned by electron beam lithography. For 1.5- mm-long laser diode, single mode continuous-wave operation with side mode suppression ratio (SMSR) as high as 30dB is obtained. The line-width of the lasing wave is kept as narrow as 70MHz. The devices show a stable single mode operation with current tuning rate of 0.01nm/mA.

In view of whether the optical system of a focal length 14~360mm continuous zoom TV can obtain high quality and high reliability images in high and low temperature environment, especially in extreme low temperature environment. The thermal design of zoom TV optical-mechanical system using passive thermal control and active thermal control is proposed. The passive thermal control uses polyimide as insulation material to increase the thermal resistance between the camera interior and the outside. Active thermal control uses electric heating film to dynamically heat the key parts of the camera lens. Under the condition of low temperature, the finite element method is used to establish the heat transfer model of the whole lens assembly in the workbench finite element software, and analyze the heat load composition, including the heating power load, the heat convection load and the heat radiation load, and carry on the steady state thermal analysis. Through thermodynamic analysis and experimental verification, the consistency of focal plane of zoom camera optical system is good after taking active thermal control measures at the extreme low temperature of -45°C. The optical transfer function (OTF) of zoom lens at cut-off frequency (100lp/mm) is 0.25 higher than that before thermal design, which can meet the requirements of thermal control design with better transfer function distribution and higher imaging quality. The correctness of the simulation results and the rationality of the optical-mechanical design are verified.

The primary mirror of AIMS solar telescope is heated during the observation of the sun, leading to temperature rise of the primary mirror. The temperature difference between the primary mirror and the surrounding air may cause the seeing effect (mirror seeing), which is one of the key factors influencing the image qualities of the telescope. In this paper, the temperature fields of the primary mirror and its surrounding air are simulated by the CFD software on the conditions of different ambient wind speeds, different observational angels of the primary mirror, and the duration of observation. According to the calculation of temperature fields, the mirror seeing on different conditions are analyzed and the necessity of thermal control of the primary mirror is evaluated. The evaluation of the mirror seeing is very helpful for the design of thermal control of the primary mirror.

Laser beam quality is an important parameter to evaluate the spatial characteristics of laser field. Based on the Wigner distribution function, the beam quality characteristics of one-dimensional field are analyzed and the beam quality factor is divided into intensity term, wavefront term and coherence term. The model shows that the incoherence in laser field affects the coherence term of the beam quality through the incoherence coefficient k(x₁,y₁,x₂,y₂), and then affects the beam quality of the whole field. The beam quality evolution trend of diode lasers with mode hopping or multi-mode in longitudinal mode is analyzed by simulation. It is shown that when the order of longitudinal modes in the laser increases, the influence on the beam quality is related to the laser field distribution, the depravation of beam quality is proportionally related with the transverse mode component of diode lasers.

Special processing of rapid thermal annealing on the cavity coating films for 1950 nm wavelength antimonide quantum well Laser diodes are studied. The maximum output power of the laser is greatly improved by RTA process on cavity facet films from around 610mW to above 700mW. The power conversion efficiency is further improved by the simple process by 23.2% than that of the laser coated. And the laser devices become more reliable and have extended service life after the process.

One-dimensional photonic crystal exhibits unbelievable performance in designing large-mode-area fiber and fiber Bragg gating for high power fiber laser. However, the property of one-dimensional photonic crystal is sensitive to its structure and refractive index distribution, which may change due to the non-negligible thermal effect resulting from the hyperthermal working condition. In this paper, the thermal effect on one-dimensional photonic crystal is analyzed on the basis of heat transfer theory, Bragg reflection theory and finite element method(FEM). Firstly, with the help of heat transfer theory and finite element method, the temperature fields of the one-dimensional photonic crystal subjected to different heating sources are calculated. By making use of the calculation results, the deformation of the photonic crystal bringing from the temperature field is estimated. Then, the thermal effect on the transmission spectrum of the one-dimensional photonic crystal is analyzed. These studies not only provide important information for the manufacture of high power fiber laser but also may help the designers of fiber laser to find methods of counteracting the thermal effect.

We propose a hollow-core photonic bandgap fiber (HC-PBGF) with background composed of two materials to support orbital angular momentum (OAM) modes. Numerical models are set up to figure out the effective indexes and confinement losses over 1.3-2.0 μm. Simulation results show that this fiber can support more than 48 OAM modes, of which the effective indexes satisfy the condition for effective index separation (<10-4) and the confinement loss keeps under 10^-7 dB/m over 1.3-2.0 μm. According to the comparison between fibers with same structure but comprising one or two background materials, adopting two materials to compose background is an effective method to significantly improve the performance of OAM-supporting HC-PBGF. The HC-PBGF proposed here is competitive in dealing for OAM multiplexing for optical communication systems.

The semiconductor epitaxial design and lasing characteristics of an optically barrier-pumped GaSb -based semiconductor disk laser (SDL) emitting at 2.0 μm optimized for resonant optical barrier pumping around 1470 nm are presented. Compared to conventional barrier-pumped devices with pump wavelength of 980nm, the novel barrier-pumped device with the smaller quantum deficit reaches a significantly higher power efficiency, and thus a higher output power at a given pump power, due to the lesser internal heat generation. Using an intracavity SiC heat spreader, a cw output power in excess of 300 mW has been achieved at a heat sink temperature of +15 °C, and still more than 500 mW at +10 °C.

In order to meet the requirements of high-precision alignment of primary and secondary mirrors of space camera in thermal environment, we develop a new supporting structure which can eliminate heat affect between mirrors automatically. Through the simulation analysis, we have verified this structural design is feasible. According to requirements of the optical system, an integrated machining scheme with three-bar supporting structure for the secondary mirror is proposed. The automatic athermalization of the primary and secondary mirrors supporting structure is confirmed by structural analysis and optimization. The displacement between the primary mirror and secondary mirrors in the thermal environment range of -20° ~ +60°C is analyzed by using the PATRAN software, and the results show the position change is within 0.01mm. The structural size of the secondary mirror supporting cylinder is optimized, and the effect of stray light suppression for the multilayer sleeve visor is analyzed and verified by using the TRACEPRO software. The results show that the proposed structural design can achieve the high stability of the primary and secondary mirrors supporting structure and the good effect of stray light suppression.

A mathematical model of the diffraction efficiency change with the ambient temperature for the double-layer harmonic diffractive elements (HDE) is presented, and its effects are analyzed in this paper. The double-layer HDE structure is investigated and the optimization procedure is based on the equation of diffraction efficiency of the double-layer HDEs. By selecting appropriate design wavelength, the average diffraction efficiency of the system is reaching 99% in working wavelength and working temperature, which improves the image contrast and the image quality significantly. A set of dual-wavelength infrared optical system is designed based on dual-wavelength 320x240 element cooled thermal IR focal plane arrays detector. By introducing double-layer HDEs and aspheric surfaces, the chromatic aberration and the off-axis aberration are well corrected and the system structure is simplified. The system working in the wave band of 3.7~4.8μm and 7.7~9.5μm and with the F number of 2 is consisted of 8 elements and has 100% cold shield efficiency. The image quality evaluating results show that the performance of the dual-wavelength infrared optical system is very well in temperature from -40C° to +60C°.

In order to meet the requirements of the new laser radar and laser active lighting for the miniaturized line light source, a linear laser light source that can be transmitted over long distances has been successfully designed and prepared. This linear laser light source is based on 808nm semiconductor laser. Firstly, a set of orthogonal placement plano-convex aspherical lens is used for collimating the laser beam of gauss distribution, thus the parallel beams that can be transmitted over long distances is obtained, and then through the Powell prism. Finally, the semiconductor laser is shaped into a laser light source with the slender and uniform intensity distribution. And we also have carried out an example design simulation with the Zemax optical design software and built an experimental system, and a laser light source has been successfully prepared with the divergence angles 54° of the fast directions and the uniformity 23.5% of the linear spot. The experimental results can match the Zemax simulation results well, which proves that the design method in this article is correct, simple and useful.

We can get the useful information of the targets from the polarization of it. In many cases, the polarization of the target changes with wavelength. Channeled spectropolarimetry (CSP) is a powerful tool to measure the spectrum and polarization simultaneously in one snapshot. However, the resolution of recovered spectrum is severely reduced by the aliasing between channels, which greatly limits the application of CSP. In this paper, aliasing reduction for CSP using Super-resolution technique is presented. An interferometer based on Savart polariscope is implemented and the channeled interferogram on detector is slightly tilted to get the super resolution sampling. We can increase the optical path difference (OPD) largely without the limitation of the detector. The spacing between channels will also increase, which will reduce the aliasing between them. The feasibility of that method is proved by the simulation results.

For a certain type of needle valve coupler under the working condition, the high pressure oil is easy to leak from the contact end face of the needle valve body and the needle spring seat, so the Solidworks software was used to establish the overall 3D model of the needle valve coupler and design different micro concave structures. Then use Ansys simulation analysis software to simulate the working conditions to statically simulate the micro-concave structure on the needle body. According to the simulation analysis results, the micro-concave structure on the needle valve body was optimized, so that the high-pressure oil leakage problem was improved.

Hyperspectral images (HSI) have a strong ability in information expression, and sparse subspace clustering (SSC) model for HSI have become very popular in recent years. Due to polarization information has a good performance on the edges and roughness of materials, adding polarization information into HSI clustering can give better results. In this paper, a fast spectral-polarized sparse subspace clustering (FSP-SSC) algorithm combining hyperspectral information and polarized information is presented. Furthermore, a new framework in the manner of sampling-clustering-classifying is used to reduce the computational complexity of the algorithm: firstly, super pixels which are segmented form original images by simple linear iterative clustering (SLIC) are sampled; then the samples are clustered by solving the optimization problem considering both of hyperspectral information and polarized information; after that, we can get the final cluster results by classifying non-sampled super pixels into the clusters based on the sampled super pixels. Some experiments have been performed to demonstrate the accuracy, efficiency and potential capabilities of proposed algorithm.

In this paper, a full information vector recognition algorithm for moving targets is proposed on the basis of the characteristic distribution of point targets and the moving characteristic between frames. The traditional multi -frame image fusion method of moving target recognition is abandoned. We utilize the distribution characteristic of point targets extracted from single image and moving characteristic of point targets extracted from multiple images to recognize and classify moving targets with the similarity principle of feature vector. Compared with the traditional maximum likelihood estimation image processing algorithm, the proposed recognition method costs less computation and provides a novel approach for spatial moving target detection and recognition.

We present a fabrication method for 3D microtransformers with air core inside silica glass by means of femtosecond-laser-wet-etching (FLWE) and metal-microsolidifying, for very high frequency applications. A fabricated transformer with 24turns of primary coil and 12 turns of secondary coil，yielded an inductance of 70nH and 55nH. The maximum transformer efficiency of 62% was measured at a load of 50 Ω. Finally, the embedded 3D micro-transformer can be easily integrated with other microelectrical, mechanical and optical systems, applying in MEMS, sensors and lab-on-chips.

Here we report the solid source molecular beam epitaxy (MBE) growth of high quality of InGaAs/ GaAs quantum dot (QD) structures. A laser device is fabricated by the semiconductor process, including Lithography, Inductively Coupled Plasma (ICP), Plasma Enhanced Chemical Vapor Deposition (PECVD) and Reactive Ion Etching (RIE). The rigid is 100μm wide and cavity is 2000um long. Room temperature continuous-wave (CW) operation with emission wavelength around 1.31μm is presented. Threshold current (I_th) and threshold current density (J_th) is 0.3A and 150A/cm² at 15°, and output power at I_th=7A reached as high as 1.079W. We also observe that the spectrum shift from 1315nm to 1333nm when the injection currents increase from 1.5A to 3.5A, and the shift speed is 8.72 nm/A.

A molybdenum disulfide (MoS₂) saturable absorber (SA) solution is fabricated by liquid-phase exfoliation (LPE) method. By using the MoS₂-SA solution, a compact diode-pumped passively Q-switched Ti:Sapphire laser has been demonstrated. The minimum short pulse width is 3.7 ns and the maximum pulse energy is 16.2 μJ at 1 kHz repetition rate. Our results show that MoS₂-SA solution can be developed as an effective saturable absorber to achieve nanosecond pulse laser in the infrared range.

For a wavefront tested by Shack-hartmann wavefront sensor, the zonal integration method is often chosen by researchers to solve the reconstruction problem. But it has shown an unacceptable result when the phase derivative data is distributed on an unconnected domain, the obtained wavefront will contain different piston error on each subdomain. Therefore, a new zonal wavefront estimation algorithm is proposed to deal with this drawback, which uses a simultaneous fit method to correct piston error of each subdomain. The validity of the algorithm is verified by a numerical simulation and experimental results.

In order to ensure the on-orbit performance of space laser communication terminal(SLCT), the optical performance test under thermal vacuum conditions must be completed on the groud. In this paper, according to the requirements of SLCT, thermal vacuum optical performance test system was designed and developed. Its main testing capabilities include the divergence angle, polarization state, wave aberration, transmission power. Several SLCTs were tested by the system, the results show that the overall performance of the test system is stable and the thermo-optical test of SLCT can be completed well.

Doppler asymmetric spatial heterodyne spectroscopy (DASH) with its high stability and feasibility of synchronized calibration highly suit for the wind field observation. By applying the synchronized calibration, the thermal phase distortion of observation emission line could be corrected greatly based on the similarity of thermal effects between observation emission line and calibration line. While, the correction residual which could be called relative thermal phase distortion still influence the wind measurement precision significantly. In this manuscript, we discuss and analyze the relative phase distortion of DASH theoretically and practically based on the DASH retrieval theory and the experiment. Firstly, based on the retrieve theory of DASH, we analyze the relationship between the relative phase distortion and the precision of the wind measurement. It is found that 1.528mrad phase error equal to 1m/s wind measurement error for the DASH developed by our research group. Secondly, based on the DASH developed by our research group, laser of 632.8nm and Ne lamp are employed as input source to test relationship between relative phase distortion and internal temperature of interferometer. According to the experiment result, the relative phase distortion change weekly with the variation of temperature between 25.14°C and 25.67°C. While, the relative phase stability decrease rapidly in other else temperature range. Lastly, according to the experiment result, we analyze the major source of relative phase distortion which could make contribution to reducing the relative phase error, which could increase the wind measurement precision, in the future research.

In this paper, an image enhancement algorithm based on Contourlet transform is exhibited. The feasibility of the enhancement algorithm is verified through various pyramid and directional wavelet filter combinations. The enhanced images are evaluated by both the subjective and objective approaches. It provides us an alternative method to enhance the image contrast.

Dues to its large capacity of information, super-speed transmission and high stability, laser communication has become a popular kind of satellite communication technology. Different from other kinds of communication technology, laser communication terminals (LCT) consists of optical systems with high imaging quality, high precise and rapid tracking systems. Testing the LCT on land is necessary to ensure its performance on the satellite. This article introduces a LCT-test and evaluation station (LCT-TES) in the laboratory. The LCT-TES is a high quality optical system providing laboratory measurements of the key characteristics of LCT, such as power testing, energy distribution of light spot in the far field, and the angle of beam divergence. The test precision of LCT-TES is also analyzed in this paper.

Digital image facilitates further cultural exchanges while its potential safety hazards is becoming gradually aus- tere. Therefore assembling the characteristic superiorities of optical chaos and embedded hardware, experimental implementation of image encryption is of great academic value and application prospect. In this paper, we ex- perimental implement a color image encryption system based on optical chaos with ARM-embedded hardware. A vertical-cavity surface emitting laser (VCSEL) subject to positive optoelectronic feedback is utilized in the experiment, and the chaotic signal is gained under suitable parameters. The chaotic optical signal is trans- formed into optical chaotic data through an analog-to-digital converter. In our experiment, optical chaotic data dominates the image encryption process where the improved gravity model and the double sine map are served to encrypt the color image. The encrypted image can be conveyed securely through cloud services, and then our hardware board can inerrably decipher the encrypted image. Experimental results visibly illustrate that we successfully realized the encryption of color images.

Imaging polarimetry has emerged over the past decades as a powerful tool to reveal the information invisible in intensity image. This paper aims at the application of division of focal plane (DoFP) imaging polarimetry in metal surface inspection. We obtain the intensity image and polarimetric image of some metal components on which there are defects, including scratch, wear, crack and burr. Experiment shows that polarimetric imaging can reduce the effect of strong reflection and improve the defect/surface contrast. The polarimetric image is more effective for metal surface inspection than the traditional intensity image.

Aerosols such as fog and dust interfere with the backscattering of laser proximity detection, which severely limits its application range. In order to achieve target recognition under aerosol interference conditions, the study of backscattering law is carried out. Based on Monte Carlo simulation method, the model of lidar interaction with aerosol is established, and the time domain characteristics of backscattering of laser radar are simulated. The peak intensity, signal delay and waveform broadening of backscattering echoes under different extinction coefficient (visibility), scattering coefficient and absorption coefficient were studied. The conclusions obtained from the study have certain reference significance for understanding the backscattering effect of aerosol particles, and also have certain significance for the subsequent research of anti-aerosol interference of laser detection.

X ray CT is a vital technology for inspecting the internal structure of some objects. Various computing method models have been used to CT reconstruction. When image of the scanned object is recorded by the detector unit of finite area, the strip-based projection model is more suitable. In this paper, a simultaneous algebraic reconstruction technique (SART) for strip-based parallel beam projection model have been adopted. Furthermore, in order to reduce the radiation dose and avoid the blurring effect resulting from changes in physical and chemical properties of specimens during scanning, it is necessary to reduce the number of step-scanning. This algorithm combined with cubic spline interpolation can reconstruct high quality CT images in a small amount of data projection in numerical simulation.

The retroreflector array consists of multiple cubic corner reflectors, and is used as a cooperative target for space attitude measurement. The position and normal direction of each cubic corner reflector directly affect the measurement accuracy. From the point of view of structural design, a series of practical precision extraction methods are put forward based on machining accuracy in this paper. After the verification of some experiments, the accuracy of the method can be controlled within 5', and the position accuracy is better than 0.05mm.

The tunable localized surface plasmons in novel antenna of Au nanosphere dimer coated by graphene is studied theoretically. We demonstrate the electronic tuning of graphene based Au nanosphere antenna via modifying the Femi level of graphene for realizing active tunable localized surface plasmons. It is found that localized electronic field shows an evident increasing, as the graphene layers increase. The resuts are explained as the more evidently enhanced resonance of localized surface plasmons for multilayer graphene than monolayer graphene nanoantenna when the incident light matches to the resonance wavelength of the Au-graphene hybrid system. In addition, it is revealed there is observable blue-shift for the resonance wavelength when the graphene layers get increased. The study provides basic understanding for tuning graphene based on Au nanosphere antenna for a wide range of applications such as single-molecule fluorescence, SERS and photothermal therapy.

Road surface meteorological conditions are very important for traffic safety. According to the statistics, the ratio of traffic accidents that occur on icy, wet and dry road surface is about 4.2:1.6:1. A remote road surface meteorological condition sensor based on multi-wavelength light was developed in this paper which could identify the road surface condition including dry, wet, icy and snow, that may be vital for preventing traffic accidents. By using multi-wavelength optical remote sensing technology and near infrared light source, the diffuse reflectance spectrum of road surface can be detected. The four road surface states of dry, wet, ice and snow can be measured with non-contact method, and the thickness of pavement water film can also be measured. Such road sensors were used on G50 highway in Chongqing, China. Experiment results show that the system could meet the requirements well.

A new type of laser radar system with off-axis parabolic rotating surfaces and a hyperbolic plane-convex lens configuration is designed in this paper. Three dimensional vector theory of reflection and refraction are utilized to design and analyze the structural parameters of the system. Ray tracing simulation are performed and results show that the new system can greatly decrease energy loss which is caused by central reflection from the secondary reflector in cassegrain-type antenna. In ideal conditions, the divergence angle of the transmitting rays can be compressed to 0.04 mrad. The incident lights will converge to the fiber core if the incident angle is less than 0.65 μmad. This design provides a practical way to improve performance of laser radar system.

The visibility of calculation between patches in complex 3D scene can reflect the occlusion relationship between patches, which is the premise of calculating the radiation effect between patches due to self-emission or light reflection. In the 3D light field of remote sensing scene radiation distribution calculation, full chain optical imaging refinement simulation and other fields have a wide range of applications. At present, there are some problems in the study of the visibility of calculation between patches in complex scenes. Firstly, existing visibility of calculation method based on viewpoints of perspective is easy to miss some visible areas. Secondly, the number of patches in complex remote sensing 3D scene reaches tens of thousands or even millions, the computational complexity of visibility of calculation between patches reaches O(N2), and the existing serial calculation method is time-consuming and difficult to apply. Therefore, this paper carries out the study of the visibility of calculation and efficiency optimization between patches in complex 3D scenes based on super-calculation. A new method for calculating the visibility between patches based on hemispherical uniform random sampling is proposed. The correctness of the algorithm is analyzed theoretically. The visibility of parallel computing model is designed according to the proposed algorithm and experiments is verified on the super computer. The experimental results show that for the 3D application scene of millions of magnitude, compared with the traditional visibility of serial processing strategy, the parallel processing of 512 nodes of the super-calculation platform "Tianhe II" can achieve an acceleration ratio of nearly 500, which improves calculation efficiency significantly.

Sparse aperture masking technique is based on principle of optical interference, it has high spatial resolution and is especially suitable for star diameter detection. It transforms telescope into a Fizeau interferometer by a simple action of placing an aperture mask over the pupil plane. In this paper, we explain its principle, simulate whole process on computer and develop our data processing method. Finally, we design a simple optical system in laboratory for experimental verification, in which stellar source is reproduced by a pinhole illuminated by a laser, choosing four sub-aperture mask on pupil plane, by measurement of interferogram visibility, we successfully acquire star diameter.

Thermal reflow is widely used in the fabrication of microlenses as a simple and low-cost process, which includes the direct contact heating and the upside-down reflow. To compare the difference in the shapes of the microlenses obtained by these two approaches, the cylindrical microstructure arrays obtained rapidly via DMD-based lithography system were used for different thermal reflow processes, and subsequently, two types of high-fill-factor microlens arrays (MLAs) were fabricated and measured in the experiment. Results indicate that the MLAs obtained by these two kinds of thermal reflow have different surface profiles, while these MLAs are good in surface quality because the profile curves of each microlens are very similar and continuous. The comparison results provided in this paper can be used as a reference for selecting the appropriate thermal reflow process for fabrication of other microlenses.

In this paper, a novel microscopic imaging technology, termed light field Fourier ptychographic microscopy (LFFPM), is presented which enables the reconstruction of wide-field, high-resolution images with the depth information by utilizing a light-emitting-diode (LED) illumination matrix.Conventional light field microscope lacks the ability of high lateral resolution because it sacrifices its lateral resolution to its angular resolution. Compared to conventional light field microscope, LFFPM enhances the lateral resolution with no need for the object to be in focus. Using LFFPM, the result shows that the lateral resolution is more than 2 times better than light field microscopy in simulation and 1.5 times in the experiment. Furthermore, the simulation result also shows that the ability of LFFPM to recovery the information of the phase and amplitude.Thus, this technology has a wide prospect of various biomedical applications such as neuroanatomy and haematology.

Glass preparing and integrating technologies are important in construction of grazing incidence optics, and these vital process are corresponding to the concentrating efficiency directly. Thermal slump glass under pressure supplied by stainless cloth with mass has been shown in this paper, and we obtained a below 1 nm roughness by coating Ir on slump glass segments. Then, A novel 6 dimensional integrating system for grazing incidence optics was developed to assemble all segments together, carbon ribs and epoxy were applied in the integrating process to make fragile glass segments stable. Finally, a glass-carbon-epoxy structure grazing incidence optics was developed and focal spot with diameter of 6 mm was obtained with parallel light. This kind of grazing incidence optics is supposed to concentrate large area X-ray photons to small area for reducing cost on space applications.

The main influencing factor of imaging under high speed conditions is the aero-optical effect. Aero-optical effect is a kind of noise, which can be regarded as a superposition of three kinds of noises, system noise ，aero transmission effect and aero heat radiation effect. In this paper, we only consider aero transmission effect and aero heat radiation effect. The simulation and correction of aero-optical effects are important for terminal guidance. The aero-optical effect simulation method described in this paper uses a deep neural network (Conditional Generative Adversarial Networks). The use of big data allows the conditional generative adversarial networks to learn the mapping between clear pictures and pictures with aero-optical effects in training. Aero-optical effect correction is usually divided into two parts, the correction of the aero transmission effect and the correction of the aero heat radiation effect. In this paper, we use the conditional generative adversarial networks to train a large amount of data and learn the mapping relationship between the pictures with the aero-optical effects and the clear pictures in the training. And this mapping relationship is preserved in the form of bias and weights. It is not necessary to consider the aero-optical effect and the aero heat radiation effect separately. In this paper, the structural similarity (SSIM) between the real image and the simulated image generated by the conditional generation adversarial the network is 97.63%. The structural similarity (SSIM) between the clear image and the aero-optical effect image corrected with the conditional generation adversarial the network is 76.59%. The structural similarity (SSIM) between the original aero-optical effect image and the clear image is 55.73%.

In this paper, we review our recent work on the statistical properties of polarization speckle with its unique properties of random polarization states fluctuating in space. From random walks of polarization phasor, we provide the origins of the polarization speckle by taking the vector nature into account for stochastic electric fields. Based on the random polarization phasor sum as an extension of conventional random phasor sum, the first and second moments of the Stokes parameters of the resultant polarization speckle have been examined. Two types of devices for polarization optics, i.e. rough-surfaced retardation plate and random polarizer array, will be introduced as the physical realization of the desired phenomena of polarization speckles. Some statistical properties of the stochastic electric fields are reviewed in order to understand the performance of these two polarization optics devices for generation and development of the polarization speckle.

In order to improve target recognition and accurate positioning, A Non-synchronous processing method base on distributed laser warning signal has been put forward。 First, Work principle and system constitution of distributed laser warning are introduced. The time information of receiving the alarm are exported by pulse form when laser warning device received threat warning signal, then this warning signal are processing and export warning position and other data information by the bus form. The processing center of the warning data receives time information and data information from different sensors. Finally, these not- synchronous warning information carry on fusion with synchronous processing by means of time scale and deviation value. Concrete warning position are obtained through the method and high accuracy recognition probability is achieved, which has higher engineering application value.

Beam steering is an important part of achieving target searching, aiming, tracking, capturing and imaging. It has important applications in the fields of new system laser radar and space laser communication. In this paper, the basic principle of optical phased array (OPA) beam steering is detailed, the development status and research results of OPA beam steering technology based on liquid crystal, optical waveguide and MEMS are introduced, and the application of OPA beam steering technology is briefly described. Finally, the prospect of optical phased array beam steering technology is prospected.

In the ion beam figuring(IBF) process, a stable removal function is the premise of ion beam figuring, and the information of removal function is generally obtained by experimental methods. Based on the study of removal function model, the stability of the removal function is analyzed by line scan method. A line scan experiment was performed on a 50mm diameter optical component, within 1h, the removal function's peak removal rate varies in 0.74%, full width at half maximum (FWHM) varies in 0.41%, and volume removal rate varies in 2.62%. The removal function is stable and can be used for actual ion beam figuring. Using this method, the stability of the removal function can be verified to ensure that it satisfies the figuring requirements.

The Integration Test Bed (ITB) is a large-aperture single-beam Nd:glass laser system, built to demonstrate the key technology and performance of the laser drivers. The phase II designed output of the ITB at 1053nm is 18.2kJ with the peak power of 3.6TW. So it is important to keep a flat spatial intensity profile at the end of the system to avoid optical elements damage or small-scale self-focusing. Applying the Liquid Crystal Programmable Spatial Shaper (LCPSS) to compensate the beam non-uniformity related to amplification and transmission is an effective way at present. In this paper, we attempt to pre-compensate the beam nonuniformity by the LCPSS. Experiments were carried out to study the spatial fluence modulation and contrast improvement at the main laser output of the ITB laser facility. The results show that the peak-to-average fluence modulation in the near-field is typically 1.35:1; the contrast is about 0.08, at the designed energy and power, which meet the modulation less than 1.4:1 and the contrast under 0.1 design requirement.

The blue laser diode (LD) illuminator in this study was composed of a cerium doped yttrium aluminum garnet (Ce:YAG) crystal, a 450-nm laser diode and an optical fiber. After a first-principles calculation, the energy gap of the Ce:YAG crystal was found to be 4.71 eV, which was less than that of the YAG. The luminescent properties of the Ce:YAG were determined by the electronic distribution of the Ce (d) and Ce (f) orbits. The Ce:YAG crystal had two characteristic absorption peaks of Ce³⁺ at 332 nm and 455 nm. Hence, the 450-nm LD excited fluorescence spectra of a Ce:YAG crystal can be used for laser illumination. We discovered that the luminous efficiency of the LD increased with increasing color temperature for 4000 K, 5000 K, 6000 K and 6500 K but not for 3500 K, due to the low light transmittance of the thickest Ce:YAG crystal. The highest color-rendering index was about 70.0. Also, the blue laser without the 430-nm light from spectral radiance was, compared to an LED, a more serious eye hazard. We calculated that the permissible exposure time of the LD was longer than that of an LED. We also discovered that LD illumination is more secure than LED illumination.

The scattering of defects on the surface of the mirror directly affects the performance and accuracy of the optical testing system. The scattering of the surface defect of the mirror can be detected by the laser scattering microscope. In order to ensure the detection efficiency and precision of the whole system, the microlens lens, the size of the spot and the power spectrum response of CCD are designed in the design of the hardware system. secondly, the laser scattering microscopic imaging test system is programmed on the software system, which can use the stepping motor to scan the surface of the mirror, and control the image acquisition card to capture the image and display it visually; To obtain the scattering image of defects, it is necessary to study the laser scattering laws of various types of defects, and to select a reasonable microscopic imaging Scattering theory for a specific type of defects. focusing on the effects of different incident angles of light sources and scattered light at different angles of the same incident angle on the imaging quality of defects, and the relationship between laser irradiation and smear scattered light imaging in the spatial domain is obtained. A high-quality plaque scattering image lays a solid foundation.

Pneumatic loading system is an important part of the control system of double-sided polishing machine. It realizes ultra-precision polishing of work piece by accurately controlling the pressure of the upper polishing disc loaded on the upper surface of the work piece. Pneumatic loading system is a typical nonlinear, time-varying system. The traditional PID control parameter setting is very complex, and it is difficult to meet the control requirements. In order to accurately control the parameters of the PID control, this paper will join the fuzzy control block in front of the PID control, make error and error change rate as input of fuzzy control, and PID control parameter as output, according to the selected membership functions and fuzzy rules correction the PID control parameters in real time, constitute adaptive fuzzy PID control. This control strategy can effectively control the pneumatic loading system, with strong stability and robustness. To achieve the stable control of polishing pressure, satisfy the accuracy requirements of medium and large diameter double-sided polishing machine.

The value range of AoP (angle of polarization) is physically limited to [0, π]. However, for most programing languages such as Matlab and C/C++, the range of inverse tangent function is commonly limited to [-π/2, -π/2]. Therefore, this paper derives a practical formula for AoP calculation based on the inverse tangent function of common programming languages. Because AoP is a periodical function, the conventional gray image cannot effectively display the AoP levels. The hue component of HSV (hue, saturation and value) color space is also periodical. Therefore, this paper maps the AoP to hue component and then transforms HSV space to RGB space. Different AoP reference orientations will produce different false color displays. In our experiment, polarization images of a fishbowl scene are captured by a DoFP (division of focal plane) polarization camera, and a sequence of false RGB images with different reference orientations are produced.

Refractive index variations caused by temperature or pressure gradients in transparent fluids are invisible to the naked eye. Schlieren effect reveals this variation using refraction and the knife-edge method. High contrast schlieren images are important in the analyses of fluid flow, gas density, shockwaves, heat transfer, flames, ballistics, leak detection and other applications. The neglect of physical or wave theory in schlieren technique leads to erroneous results in some circumstance. Specifically, a study had mathematically shown that illumination is fairly uniform over large part of the field but suddenly increases at the edge and is fairly appreciable for some way outside the actual physical boundary of the aperture. This bright edge is noticeable in all schlieren systems whereas a geometrical optics would lead to a uniformly illuminated field. Geometric ray-tracing codes are useful for optical design, but they cannot describe the key role of diffraction in the formation of schlieren image. In this study, a wave propagation-based model of the schlieren technique is proposed. Compared to the ray optics approach, the proposed model provides valuable insights and visualization of fluid flow dynamics. Some predictions of the model will be confirmed through experimental demonstrations. Setup parameters are also optimized resulting in enhanced resolution of schlieren images.