ITF is usually over looked during the deflectometry measurements, especially when low spatial frequency errors are the main test focus. However, real data shows that the effect of ITF cannot be ignored to reach high accuracy measurements of high spatial frequency features. We illustrated with simulation that ITF of SCOTS is proportional to the camera imaging MTF. We then applied this result to the edge measurement data of a large mirror, where a better agreement is achieved between SCOTS test and a test-plate interferometric test after the compensation. Experimental verification of the ITF theory for deflectometry is preliminary performed. The results will be summarized in our following paper.

In this paper, a ridge algorithm which is based on wavelet analysis is adopted in the measurement of in-plane displacement. To measure in-plane displacement by electronic speckle pattern interferometry (ESPI), a series of speckle patterns are captured with the help of a CCD camera which is known as temporal speckle pattern interferometry (TSPI) technique and TSPI technique has better correlation and a larger measuring range compared with ESPI technique. To retrieve the phase fluctuation caused by the displacement of specimen, three types of complex wavelets are selected in the wavelet analysis to compare with the traditional Fourier analysis.

The paper researches on a high precision displacement measurement system mixing double-wavelength interferometry and single-wavelength interferometry by waveform transforming based on Fast Fourier Transform (FFT) technology. The signal of double-wavelength interferometry is used for determining the amplitude of the measurand which makes the measurement range be as large as half a synthetic-wavelength, while that of single-wavelength interferometry is for measuring the value of the measurand precisely which endows the measurement resolution to be as high as less than 1nm, for the amount of the interference fringes of the signal of single-wavelength interferometry during the shifting range of the peak of the signal of double-wavelength interferometry demonstrates the value of the measurand. However, as the signal of double-wavelength interferometry is cosine amplitude modulated, the peak area of it is flatten and the peak position is difficult to be determined, which will influence the measurement precision directly. In order to address the peak position of the double-wavelength interferometric signal accurately, we transform using FFT technology the cosine amplitude modulated signal of double-wavelength interferometry into a triangle-wave amplitude modulated signal to make the peak position prominent. It is very easy to determine the peak position accurately and the amount of the interference fringes of the signal of single-wavelength interferometry during the shifting range of the peak will also be determined precisely. High precision displacement measurement with large range and high resolution could be realized.

Extended source interferometer, compared with the classical point source interferometer, can suppress coherent noise of environment and system, decrease dust scattering effects and reduce high-frequency error of reference surface. Numerical simulation and experimental verification of extended source interferometer are discussed in this paper. In order to provide guidance for the experiment, the modeling of the extended source interferometer is realized by using optical design software Zemax. Matlab codes are programmed to rectify the field parameters of the optical system automatically and get a series of interferometric data conveniently. The communication technique of DDE (Dynamic Data Exchange) was used to connect Zemax and Matlab. Then the visibility of interference fringes can be calculated through adding the collected interferometric data. Combined with the simulation, the experimental platform of the extended source interferometer was established, which consists of an extended source, interference cavity and image collection system. The decrease of
high-frequency error of reference surface and coherent noise of the environment is verified. The relation between the spatial coherence and the size, shape, intensity distribution of the extended source is also verified through the analysis of the visibility of interference fringes. The simulation result is in line with the result given by real extended source interferometer. Simulation result shows that the model can simulate the actual optical interference of the extended source interferometer quite well. Therefore, the simulation platform can be used to guide the experiment of interferometer which is based on various extended sources.

Moiré tomography has been considered as an effective tool in studying flow fields because of its advantages such as non-contact measurement, strong anti-disturbing capability, and wide measurement range. The spatial phase-shifting method, which can simultaneously obtain several phase-shifted interferograms, can be applied in the flow field measurements by the moiré tomography when the flow field varies rapidly. In this paper, we present a new spatial phase-shifting shearing interferometry. The optical structure of the interferometry, which only consists of a crossed grating and a linear grating, is very simple. With it six phase-shifted interferograms can be acquired simultaneously. Based on the scalar diffraction theory, the explicit forms of intensity distribution of the interferograms containing the phase information can be derived and a corresponding four-step phase-shifting algorithm is proposed to extract the first-order partial derivative of phase projection from the interferograms. Finally, the spatial phase shifting optical system is used to retrieve the first-order partial derivative of propane flame phase projection produced by plane incident wave. This work is crucial to accuracy reconstruction the physical parameter of the varied flow fields in moiré tomography.

Color fringe projection systems for 3D shape measurement have been widely studied in academia because of the advantages of non-contact operation, full-field, and fast data processing. A color CCD camera and a DLP (Digital Light Processing) projector are mostly used. However, crosstalk between color channels of the camera and projector changes the sinusoidal shape of the obtained fringe patterns and then reduces the measurement accuracy. Several methods have been proposed to solve this problem, but they are either too complicated for calculating the color-coupling coefficients using a series of phase-shifting fringe patterns or unstable convergence due to the iterative technique used. This paper presents a simple method to reduce crosstalk between red, green and blue channels. Crosstalk between color channels can be seen as signal aliasing, so different wavelength in color channels can be used to keep them apart. Two wrapped phase maps are obtained by processing corresponding spectrum with FTP (Fourier transform profilometry) in each color channel. The unwrapped phase is calculated based on multi-frequency heterodyne principle. Simulated and experimental results show that the proposed method can significantly reduce the influence of crosstalk on phase calculation and improve the measurement accuracy of the color fringe projection system.

In order to study light scattering from randomly rough surface, the linear filtering method is used to generate Gaussian randomly rough surface, and the method of moments is used to calculate the scattering light intensity distribution from perfect conduct and dielectric surfaces. The calculation results show that scattering characteristics between conductor and dielectric surfaces exist several significant differences: (1) the scattering peak value of perfectly conduct is larger than scattering peak value of dielectric on the same roughness; (2) the difference between s- and ppolarized scattering results are rather small in perfectly conduct randomly rough surfaces, while there is a obvious difference between s- and p-polarized scattering results in the condition of dielectric randomly rough surfaces; (3) though in both conditions of perfectly conduct and dielectric randomly rough surfaces, there is a shift from specular to backscattering direction when incident is p-polarized light, however, in dielectric randomly rough surface situation, the shift is much more obvious than in conduct situation.

We propose a new method to measure the birefringence changes in bulk crystals based on the typical Sénarmont configuration. The configuration comprises a linear polarizer, a sample, a quarter-wave plate, an analyzer(P.S.C.A). An external modulator is inserted in the experimental Sénarmont setup. We present a complete analysis of the optical response of a Sénarmont setup within Jones formulation. Compared to the conventional configurations. The new method is able to measure with a high accuracy the variations of the birefringence in any crystal.

It’s difficult to detect the ultra-weak light with conventional method. By using APD, we can transform the weak light to feeble current. And it’s a great challenge to design the low noise and high gain front-end electronics of InGaAs photoelectric detector. The first step to design is to calculate the noise margin of system and the bandwidth of system. And then, choose the appropriate amplifier of the system. Finally, design the whole circuit which is working stably. In this paper, we bring about a whole process of design and simulation of the front-end electronics of InGaAs photoelectric detector in theoretical ways.

Starting from three aspects, the paper introduces the reason and effects of glare and displays a kind of Unified Glare Rating(UGR) measuring system. Our research is dependent on the standard made by CIE and the UGR formula put forward by Sorensen, make use of digital camera, programming and digital image processing and develop a set of UGR measuring system. After testing, we find it able to measure indoor UGR and get repeatable results, which are close to the examples in CIEll7—1995 technical report. Hopefully, what the paper introduces can promote the implement of UGR standard and be avail to the simplification of the process of lighting quality evaluation.

Based on the detailed derivation of the displacement measurement principle with Jones matrix method, the optical system of the heterodyne grating interferometry that we previously proposed was modified. A reflection phase grating with smaller grating pitch was designed with rigorous coupled-wave analysis (RCWA) to improve the measurement performance. The first order diffraction efficiency of 47.35% and 56.24% were obtained for TE and TM polarization, respectively. Therefore the TM polarization was chose to enhance the signal-to-noise ratio (SNR) of the beat signal. Meanwhile, the errors of the optical system resulting from grating non-uniformity, frequency mixing, polarization mixing and polarization-frequency mixing were discussed as well. It was shown that the frequency mixing was the main source of the errors, and the modified heterodyne grating interferometry had the potential to realize nanometer resolution for displacement measurement.

As one of the most important direction of non-contact 3D shape measuring method, optical technology has been widely applied in the fields of industrial production, automatic detection, quality control, machine vision, cultural preservation, and so on. With the advent and development of high performance devices such as DLP (Digital Light Processing) projector and CCD camera, digital fringe pattern projection techniques have become a rapidly developing area. However, when four-step phase-shifting algorithm is used to calculate the wrapped phase, the intensity fluctuation of the captured fringe patterns may affect the accuracy of the final measurement results. This paper presents a novel method to eliminate the intensity fluctuation of the captured fringe patterns by using EMD (Empirical Mode Decomposition) algorithm. Four fringe patterns which have pi/2 phase shift in between need to be captured for four-step phase-shifting algorithm. In order to eliminate the intensity fluctuation between fringe patterns, every fringe pattern is decomposed into a number of IMFs (Intrinsic Mode Function) by using EMD. After being processed, the four fringe patterns have the same background light intensity and contrast. Both simulated and experimental data are tested to verify the validity of the proposed method. The results show that the intensity fluctuation between fringe patterns can be effectively eliminated to give accurate phase data.

In this paper, a method for constructing photorealistic textured model using 3D structured light digitizer is presented. Our method acquisition of range images and texture images around object, and range images
are registered and integrated to construct geometric model of object. System is calibrated and poses of
texture-camera are determined so that the relationship between texture and geometric model is established. After that, a global optimization is applied to assign compatible texture to adjacent surface and followed with
a level procedure to remove artifacts due to vary lighting, approximate geometric model and so on. Lastly,
we demonstrate the effect of our method on constructing a real model of world.

Nonintrusive measurements of infrared characteristics from engine exhaust plume are required for emission control or target tracking, due to the advantage of online measurement without affecting the exhaust plume. Conventional nonintrusive measurement techniques, e.g. the passive Fourier-transform infrared (FTIR) absorption spectrometry, lack prior knowledge of backgrounds and consume time to measure the complete infrared characteristics. Hence, an improved but simple nonintrusive method is proposed. Accordingly, a prototype system with a Mid-wave infrared imager has been developed and tested for the measurement of vehicle engine exhaust plume. Subsequently, the time-variant effective transmittance and emissivity is determined. Compared to the passive FTIR absorption spectrometry, this method incorporates a known background into the measurement and is more adequate for recording the rapidly changing exhaust plume radiation. Therefore, the accurate value of the transmittance and emissivity can be obtained. Further analysis reveals that the imager could be replaced with a dispersive spectrometer, which makes it feasible to acquire the absolute transmittance and emissivity with respect to wavelength. Thus, the concentration of specific toxic gases could be calculated following the radiance inversion technique.

Three dimensional flash imaging lidar technology is widely used in the field of military and national economic construction. The preliminary simulation research is an indispensable aspect in the design of the new lidar. In order to establish a simulation model most close to the real scene, the spatial effect of the simulation system during the laser roundtrip transmission process must be considered. This paper describes the physical mechanism of the formation of atmospheric turbulence, the power spectral density function of the distribution of atmospheric refractive index and the phase distortion due to atmospheric disturbances during light propagation in space. Then the phase-screen distribution of atmospheric turbulence is derived using power spectrum retrieval and time-dependent wavefront tilt parameter. In addition, numerical simulation is conducted using statistical methods. A three dimensional target range imaging simulation model containing laser characteristics, target characteristics, receiver characteristics and laser speckle is established. And the phase screen is introduced into the calculation model to simulate the results in turbulent atmosphere. The major contribution of this paper is transforming the influence of beam spreading and drifting caused by laser propagation in turbulent flow to the influence of target range imaging, which better reveals the diffusion and position drift of imaging on detection surface caused by turbulence. Results show that larger values of refractive index structure parameters and lidar target distance produce blurry and drifting imagery.

A variable universe fuzzy PID algorithm is designed to control the misalignment of the lithography projection optics to meet the requirement of high image quality. This paper first simulates the alignment of Schwarzschild objective designed by us. Secondly, the variable universe fuzzy PID control is introduced to feed back the misalignment of Schwarzschild objective to the control system to drive the stage which holds the objective. So the position can be adjusted automatically. This feedback scheme can adjust the variables’ universe self-adaptively by using fuzzy rules so that the concrete function and parameters of the contraction-expansion factor are not necessary. Finally, the proposed approach is demonstrated by simulations. The results show that, variable universe fuzzy PID method exhibits better performance in both improving response speed and decreasing overshoot compared to conventional PID and fuzzy PID control methods. In addition, the interference signal can be effectively restrained. It is concluded that this method can improve the dynamic and static properties of system and meet the requirement of fast response.

To satisfy rigid performance specifications, a feedback control was presented for zoom optical lens plants. With the increasing of global energy consumption, research of the photovoltaic(PV) systems get more and more attention. Research of the digital high-power solar array simulator provides technical support for high-power grid-connected PV systems research.This paper introduces a design scheme of the high-power digital solar array simulator based on TMS320F28335. A DC-DC full-bridge topology was used in the system's main circuit. The switching frequency of IGBT is 25kHz.Maximum output voltage is 900V. Maximum output current is 20A. Simulator can be pre-stored solar panel IV curves.The curve is composed of 128 discrete points .When the system was running, the main circuit voltage and current values was feedback to the DSP by the voltage and current sensors in real-time. Through incremental PI,DSP control the simulator in the closed-loop control system. Experimental data show that Simulator output voltage and current follow a preset solar panels IV curve. In connection with the formation of high-power inverter, the system becomes gridconnected PV system. The inverter can find the simulator's maximum power point and the output power can be stabilized at the maximum power point (MPP).

We propose a four-level superradiant laser system based on Cs at 1469 nm corresponding to the transition of 7S_1/2 and 6P_3/2 with a 459.3 nm pumping laser. With density matrix method, we calculate the relative population probabilities at each level theoretically. In a steady state, when the Rabi frequency is set to 3.5 MHz, 5.1% atoms are at 7S_1/2 level while 1.9% at 6P_3/2 level, which leads to the population inversion between the two levels. We design the experiment setup for the superradiant laser. In the steady state, the average photon number in the cavity is 1.1 × 10⁶. According to the further calculation, the power of output superradiant laser is 0.17 mW and the laser linewidth is 17 Hz. This calculation method can also be used in the area of optical metrology.

It is widely believed that by using a digital mirror device (DMD) as the spatial light modulator (SLM) of a programmable array microcopy (PAM), it is possible to achieve a cost-effective alternative to expensive confocal imaging devices. During the past decade, the design of such a DMD based PAM instrument has been frequently reported to enhance resolution and contrast, convincing images with improved quality are rare to be seen. The concrete implementation of a DMD based PAM instrument needs to successfully resolve multiple issues such as the adverse effects caused by the tilt angle of the micro-mirrors from the base board, the registration between a micro mirror of the DMD and the image pixel of the photo-detector and so on. In this paper, we report the design of a middle body consisting of a DMD as an independent attachment to a conventional microscope to convert the latter into a confocal imaging system, in a similar way as a filter turret that is placed below the head and the objectives of a regular microscopy to convert it into a fluorescent microscopy. Images of real objects with improved contrast are provided to demonstrate the effectiveness of using a DMD as SLM to improve the contrast of a PAM instrument. Such a PAM instrument has many advantages compared to conventional laser-scanning confocal systems including lower costs and higher imaging speeds. In addition, it allows convenient dynamic adjustments between imaging quality and imaging speed.

Compared with traditional mirrors, a membrane mirror made of flexible film material has the advantages of folding and deployable, lightweight, low cost and etc, and it is prospected to be used as large aperture space optical elements. In order to solve the problem of measuring the shape of the membrane mirror, a method based on the Shack-Hartmann wavefront sensing has been studied in this paper. The Shack-Hartmann wavefront sensing system and the principle of wavefront detection are introduced firstly. In this system, the measured wavefront is collected by the microlens of the lenslets and focus on the CCD, the light spot coordinate offsets relative to the ideal spots are got and then the wavefront can be reconstructed. Secondly, according to the optical properties of a membrane mirror, the membrane mirror wavefront detection system has been designed and established. The preprocessing of the light spot image of the testing wavefront focused by the microlens array, the determination of the centroid coordination and the algorithm of wavefront reconstruction modal based on Zernike polynomials are researched and a program for reconstructing the wavefront is written with in Matlab. When measuring, in order to eliminate the influence of other optical components in the detection system on the testing wavefront, a standard plane mirror is used to calibrate the system. A glass planar mirror made of glass with a diameter of 50mm and a known distribution of surface shape is used to verify the feasibility of the test system and the correction of the algorithm. Finally, the wavefront of a membrane mirror with a diameter of 85mm is measured and the errors are analyzed. It provides a means of measuring the shape of membrane mirror.

Volume phase holographic grating (VPHG) has the characteristics of high diffraction efficiency, high signal to noise ratio, high wavelength and angular selectivity, low scattering , low absorption and low cost. It has been widely used in high resolution spectrometer, wavelength division multiplexing and pulse compression technique.

In this paper, a novel kind of RGB primary colors beams combiner which is consisted of a transmission VPHG and a reflection VPHG as core components is proposed. The design idea of the element is described in detail. Based on the principle of VPHG, the rigorous coupled wave analysis (RCWA) and Kogelnik’s coupled wave theory, diffraction properties of the transmission and reflection VPHG are studied theoretically. As an example, three primary colors at wavelengths of 632.8nm, 532nm and 476.5nm are taken into account. Dichromated gelatin (DCG) is used as the holographic recording material. The grating parameters are determined by the Bragg conditions. The TE and TM wave diffraction efficiency, the wavelength selectivity and the angular selectivity of the transmission and reflection VPHG are calculated and optimized by setting the amplitude of the index modulation (Δn) and the thickness of the gelatin layer (d) by applying Kogelnik’s coupled wave theory and G-solver software, respectively. The theoretical calculating results give guidance for further manufacture of the element.

One of the key technologies which need to be solved in developing membrane mirror is the surface shape control of the mirror. The pressure distribution and calculation method for the shape of a membrane paraboloidal mirror are studied in this paper. According to Karman equation in circular membrane theory, the analytic expression of the radial continuous distributed pressure load used to form a membrane paraboloidal mirror with certain aperture and F number is solved out under certain radial displacement condition. Taking the example of membrane paraboloidal mirror with diameters of 200mm, 300mm, 500mm, and F number of 10, the number and the radial width of sub-electrodes are optimized. It is founded that by using multi-electrodes distribution mode that the radial width of center sub-electrode is 1.6 times longer than that of the rest concentric annulus electrodes with same radial width, the deviation between the membrane mirror shape and the standard paraboloid surface shape can be effectively reduced. The surface shape of a membrane mirror in 300mm diameter and F/10 that is formed by electrostatic stretching through a multi-electrodes plate with insulation intervals among sub-electrodes or not are simulated by using finite element analysis. It may provide a theoretical basis for practical control of membrane mirror shape.

We present the experimental observation of a phenomenon in which the reflection loss, induced by an uncoated glass sample placed in a laser cavity, significantly reduces at a series of incident angles. The light amplification condition for a laser to work can be satisfied by means of this phenomenon, though the gain is less than the loss when the sample is placed in the normal incidence. The angle ranges for the laser can keep working are intermittent, and both of the lasing range and no-lasing range become narrow with the incident angle increasing. Six kinds of optical glass samples and one birefringent sample have been tested, and three types of lasers are used to confirm this phenomenon. This phenomenon may make the anti-reflection film be not necessary for a transparent sample in some techniques or instruments based on the characteristics of laser resonant cavity. Principle and properties of this phenomenon are analyzed, and the theoretical analyses are coincident to the experimental observations. Three conditions for this phenomenon to occur, as well as the potential applications, are given finally.

In order to achieve the goal of constant output light power, the design of high accuracy digital control semiconductor laser constant current source is very important. Semiconductor laser is can be divided into load floating and load grounding two types based on the package. In this paper, a small power grounding type digital control semiconductor laser constant current source is realized by using ARM processor. By using this method, the semiconductor laser can be provided within the range of 0mA-500mA constant current. At same time, some functions such as slow start, temperature control, overcurrent protection are realized. In actual experiment test result show, the design method is stable, reliable and high accuracy.

The online measurement of the metal surfaces’ parameters plays an important role in many industrial fields. Because the surfaces of the machined metal pieces have the characteristics of strong reflection and high possibilities of scattered disturbing irradiation points, this paper designs an online measurement system based on the measurement principles of linear structured light to detect whether the parameters of the machined metal surfaces’ height difference and inclination fulfill the compliance requirements, in which the grayscale gravity algorithm is applied to extract the sub-pixel coordinates of the center of laser, the least squares method is employed to fit the data and the Pauta criterion is utilized to remove the spurious points. The repeat accuracy of this system has been tested. The experimental results prove that the precision of inclination is 0.046° RMS under the speed of 40mm/sec, and the precision of height difference is 0.072mm RMS, which meets the design expectations. Hence, this system can be applied to online industrial detection of high speed and high precision.

To deal with the problem of phase-shifting interefrometry with different unknown phase shifts, some special designed algorithms have been put forward by former researchers, such as the advanced iterative algorithm (AIA) and the principal component analysis (PCA) demodulation algorithms. This paper proposes a novel solution for it. Firstly, the captured phase-shifting interefrograms are differentiated to remove the additive background term. Then the trigonometric functions of the modulation phase can be extracted with the blind signal separation method. Simulations and experiments have been carried out to validate the feasibility of the proposed algorithm, where both open and closed fringe patterns are involved. Besides, the comparison results with the AIA and PCA algorithms are also provided.

Beam stabilization system is one of the most important units for lithography, which can accomplish displacement and pointing detection and control and includes beam measurement unit(BMU) and beam steering unit(BSU). Our group has set up a beam stabilization system and verified preliminarily beam stabilization algorithm of precise control beam position and angle. In the article, we establish beam delivery mathematic model and analyze the system inherent error. This shows that the reason why image rotation effect arises at the output plane of beam stabilization is the fast steering mirror (FSM) rotation of BSU in the process of beam stabilization. Two FSMs rotation around 45^o axis of FSM make the most contribution to image rotation which rotates 1.414 mrad as two FSMs rotation angle difference changes 1 mrad. It is found that error sources include three key points: FSM accuracy; measurement noise and beam translation by passing through of beam splitters changing as the ambient temperature changing. FSM accuracy leads to the maximum 13.2μm displacement error and 24.49μrad angle error. Measurement inaccuracy as a result of 5μm measurement noise results in the maximum 0.126mm displacement error and 57.2μrad angle error. Beam translation errors can be negligible if temperature is unchanged. We have achieved beam stability of about 15.5μrad for angle and 28μm for displacement (both 1σ) after correcting 2mm initial displacement deviation and 5mrad initial angle deviation with regard to the system rebuilt due to practical requirements.

In the solder paste inspection measurement system which is based on the structured light vision technology, the local oversaturation will emerge because of the reflection coefficient when the laser light project on PCB surface. As this, a high dynamic imaging acquisition system for the solder paste inspection research is researched to reduce the local oversaturation and misjudge. The Reflective liquid crystal on silicon has the merit that it can adjust the reflectance of the Incident light per-pixel. According to this merit, the high dynamic imaging acquisition system based on liquid crystal on silicon (LCoS) was built which using the high-resolution LCoS and CCD image sensor. The optical system was constructed by the imaging lens, the relay lens, the Polarizing Beam Splitter (PBS), and the hardware system was consist of ARM development board, video generic board, MCU and HX7809 according to the electrical characteristics of LCoS. Tests show that the system could reduce the phenomenon of image oversaturation and improve the quality of image.

3D angular deformations will be inevitable when ships are sailing, due to the changes of the environmental temperature and external stresses. The measurement of 3D angular deformations is one of the most critical and difficult issues in navy and shipbuilding industry around the world. In this paper, we propose an optical method to measure 3D ship angular deformations and discuss the measurement errors in detail. Theoretical analysis shows that the measured errors of the pitching and yawing deformations are induced by the installation errors of the image aperture, and the measured error of the rolling deformation depends on the subpixel location algorithm in image processing. It indicates that the measured errors of the optical measurement proposed in this paper are at the magnitude of angular seconds, when the elaborated installation and precise image processing technology are both performed.

The geometric conditions of diffuse illumination, 8 degree observation, specular light include (SCI) and specular light exclude (SCE) often be employed to measure the surface color of material with different gloss value. The SCE condition is usually realized by setting light trap on the integrating sphere. However, the structure of light trap has its negative influence on the light intensity uniformity, and can led to the inaccuracy of the test results under SCE or SCI condition. Due to the different sizes of the light trap, structures of the measurement instrument will led to inter instrument agreement among the measurement of sample with different gloss. This paper designs a measuring structure to measure the SCE and SCI results simultaneously; proposes a method to calculate the 8 degree gloss value based on the SCE and SCI test result; proposes a computing modal to modify the SCI and SCE measure result based on the 8 degree gloss value, experimental verifying is also carried out. The experimental results demonstrate the structure and modified model effectively reduce the negative influence of light trap. The inter instrument disagreement caused by the geometric dimension of different
light trap is significantly decreased.

Lamps and lamp system are widely used in large quantities in an era. The evaluation and control of optical radiation hazards of lamps and lamp systems is far more complicated. A special measurement and traceability facility was set up at NIM (National Institute of Metrology, China) to evaluate the optical radiation safety of lamp and lamp system, which includes a double grating spectroradiometer OL750D with two different entrance systems of spectral radiance and spectral irradiance traceable to the national primary standard of spectral irradiance by a 1000W spectral irradiance standard lamp, 40W deuterium lamp and a standard diffuser plate. The technical requirements of the measurement instrumentation used for optical radiation safety evaluation including monochromator type, wavelength accuracy, input optics, spectral scan interval and calibration sources are recommended also in this paper. Spectral radiance of a series of LED electric torches and infrared sources were measured by using the new developed system, and potential radiation hazards of retinal blue light hazard and retinal thermal hazard are calculated and evaluated. The optical radiation hazards of some samples are listed in Risk Group 2 (Moderate-Risk).

Nowadays, lots of studies show the potential value of laser echo intensity in three-dimensional reconstruction of laser detection system. However, raw intensity information could not be used without correcting, since target geometry could also influence laser echo greatly. Target angle that is the angle between laser axis and target normal is important geometry information in intensity correcting. This paper studies the method to calculate target angle, which, as a result, could have great benefits in laser intensity correcting and further in three-dimensional reconstruction. The target angle could be calculated from the mathematical model between the target angle, distance and pulse width based on the laser space translation model presented. Simulation and experimental results show that, the method proposed can calculate the target angle effectively, which have great contribution in laser intensity correction and further in three-dimensional reconstruction.

This paper presents a measurement method for straightness errors based on phase sensitive detection technique. This system consists of a single-mode fiber pigtailed laser diode, a corner cube, a position sensitive detector (PSD), and electronic components¹. The beam from single mode fiber is stable, which can be used as a datum for straightness error measurement after collimation. The PSD is used to receive the beam reflected by the corner cube. To eliminate the influence of background light, the laser diode is modulated by a sinusoidal wave current and phase sensitive detection technique is developed to demodulate the signal. Compared with a laser interferometer, the measurement accuracy is better than ±0.4 μm. A repeatability test is conducted to assess the system stability by measuring a stage three times, showing that the repeatability is better than 1 μm. This system can be easily assembled to measure straightness errors of a carriage in workshop. 1 μm. This system can be easily assembled to measure straightness errors of a carriage in workshop.

The importance of atom interferometers that have high sensitivity and super precision is well recognized in
the fields of rotation sensing, inertial and gravitational forces sensing, relativity tests, and other precision measures. So many researchers are absorbed in atom interferometers. An atom interferometer consists of many parts, among of which optical part plays a significant role because of the need of laser beams in every parts. Based on this situation and some specific quantitive requirements to laser beams, this article presents a laser frequency and power control system for atom interferometer which can realize the functions of frequency shift and scan, power stabilization and modulation, and highspeed switch. The system lies on acousto-optical modulators (AOM) and a phase-locked loop frequency synthesizer is designed in the system as a very important part which has wide capture range of frequency and well stability. The experimental results show that the designed system is available and the performances of laser through AOM are as good as expected and the phase noise of the output is restrained. In addition, the system also could be used in other instruments and devices, such as atomic clock, gravimeter, gradiometer, and gyroscope.

Resolution is one of the important indexes of examining optical sighting telescope performance. Traditional and subjective test methods generally adopted auxiliary visual instrument reading to achieve resolution test, which was greatly affected by subjective factors, and easy fatigue affected test precision, and it didn’t objectively and quantitatively reflect the resolution of measured sighting telescope. Taking aim at the test requirements, on the basis of overcoming the shortcomings of traditional and subjective test methods, and this paper designed a set of modern test system for resolution of white-light sighting telescope, which employed automatic focusing technology, CCD imaging technology, precision machinery technology, automatic control technology and computer image acquisition technology. Through automatic focusing of zoom lens and man-computer interaction, computer displayed and saved results automatically, which eliminated subjective error of the traditional and subjective test method. The experimental results showed that the test precision of resolution was 0.24″, which achieved the technical specification less than 0.5″, and the test accuracy was ensured.

The tubing internal thread plays an irreplaceable role in the petroleum equipment. The unqualified tubing can directly lead to leakage, slippage and bring huge losses for oil industry. For the purpose of improving efficiency and precision of tubing internal thread detection, we develop a new non-contact tubing internal thread measurement system based on the laser triangulation principle. Firstly, considering that the tubing thread had a small diameter and relatively smooth surface, we built a set of optical system with a line structured light to irradiate the internal thread surface and obtain an image which contains the internal thread profile information through photoelectric sensor. Secondly, image processing techniques were used to do the edge detection of the internal thread from the obtained image. One key method was the sub-pixel technique which greatly improved the detection accuracy under the same hardware conditions. Finally, we restored the real internal thread contour information on the basis of laser triangulation method and calculated tubing thread parameters such as the pitch, taper and tooth type angle. In this system, the profile of several thread teeth can be obtained at the same time. Compared with other existing scanning methods using point light and stepper motor, this system greatly improves the detection efficiency. Experiment results indicate that this system can achieve the high precision and non-contact measurement of the tubing internal thread.

Compressive Sensing (CS) indicates that when the signal of interest is sparse or compressible (i.e., sparse after mathematical transformation), one can take a small number of linear projection measurements from the signal, and reconstruct the signal almost perfectly through proper algorithm. The feature of the CS has great potential applications in that high-resolution imaging is highly desirable while large size detector array is unavailable, such as those in ultraviolet or infrared wavelength region or that in aircrafts and satellites working condition when the data transmission is a key issue.

However, CS technique still faces challenges in the signal sampling and reconstruction. Firstly, detector measurements must be nonnegative in linear optical system which is different from digital image processing. Secondly, blurring caused by practical optical system should be considered, which will destroy the effect of reconstruction.

In this paper, we discuss some kinds of phase encoding which could be used in practice imaging system. We make a compensation to solve the non-negative problem when CS applied in the practical optical system, use a small size detector to receive a general image degrading model, and reconstructed image from the single, low-solution and noisy observation through a fast and feasible non-linear algorithm, the result proves our system is robust and feasible.

To reduce the uncertainty of dissemination, the models for standard lamp of spectral irradiance data are presented. We propose a divide-and-conquer RBF neural network approach in which the spectral irradiance is divided into two subsets, and each subset is modeled with a different network. The results show that the RBF neural network model produces well generalizations while the Planck-polynomial model produces poor ones. During the generalizations, the maximum relative deviation of the RBF neural network model and the Planck-polynomial model were 0.027% and 3.46%, respectively.

Optical density (OD) measurement, which is based on the selective absorption of light and the relationship between absorbance and material concentration, is a quantitative analysis method. As a traditional method of optical-electrical detection in modern biochemical analysis field, OD measurement has more advantages than fluorescence and chemical luminescence, such as wider application and easier implementation of photoelectrical detection, thus types of biochemical analyzers are developed with this function. In this paper principle of OD measurement is firstly introduced. Secondly, many types of biochemical analyzers utilizing OD measurement are discussed from the aspects of wave-bands and detection channels, because biochemical analyzer reveals diversity with the same principle of OD measurement, when wave-bands and detection channels change. Meanwhile, different wave-bands and detection channels enrich the application of OD measurement. Finally, this paper summarizes trend of the development of OD measurement technique.

The Faraday magneto-optical effect of optical fiber has many applications in monitoring magnetic field and electric current. When a linearly polarized light propagates in the direction of a magnetic field, the plane of polarization will rotate linearly proportional to the strength of the applied magnetic field, which following the relationship of θ_F =VBl. θ_F is the Faraday rotation angle, which is proportional to the magnetic flux density B and the Verdet constant V .

However, when the optical fiber contains the effect of linear birefringence, the detection of Faraday rotation angle will depend on the line birefringence. In order to determine the Verdet constant of an optical fiber under a linear birefringence, the fiber birefringence needs to be accurately measured. In this work, a model is applied to analyze the polarization properties of an optical fiber by using the Jones matrix method. A measurement system based on the lock-in amplifier technology is designed to test the Verdet constant and the birefringence of optical fiber. The magnetic field is produced by a solenoid with a DC current. A tunable laser is intensity modulated with a motorized rotating chopper. The actuator supplies a signal as the phase-locked synchronization reference to the signal of the lock-in amplifier. The measurement accuracy is analyzed and the sensitivity of the system is optimized. In this measurement system, the Verdet constant of the SMF-28 fiber was measured to be 0.56±0.02 rad/T·m at 1550nm. This setup is well suitable for measuring the high signal-to-noise ratio (SNR) sensitivity for lock-in amplifier at a low magnetic field strength.

The 3~5um Medium Wave Infrared(MWIR) laser has gained a lot of attention for its important application values in remote sensing, medical, military and many other fields. However, there are many technical difficulties to fabricate those kind lasers, and the performance of their output power stabilities remain to be improved. In a practical application, the MWIR’s output power will be instability when the temperature changes and the current varies. So a system of reducing MWIR power fluctuation should be established. In this paper, a photoelectric system of stabilizing the output power of He-Ne laser is developed, which is designed based on the theory of feedback control. Some primary devices and technologies are presented and the functions of each module are described in detail. Among of those, an auxiliary visible light path is designed to aid to adjust WMIR optical system. A converging lens as spatial filter is employed to eliminate stray light well. Dewar temperature control equipment is also used to reduce circuit noise in IR detector. The power supply of AD conversion circuit is independently designed to avoid the crosstalk caused by the analog section and digital section. Then the system has the advantages of good controllability, stability and high precision after above designation. Finally, the measurement precision of the system is also analyzed and verified.

The high-energy laser, as one of directed energy weapon, is famous for its unique advantage of speed-of-light response which was considered as an ideal weapon against anti-ship missile. This paper commits to evaluate the damage process of missile by high-energy laser weapon. We analyze the propagation properties which are susceptible to atmospheric attenuation effects, atmospheric turbulence effects, thermal blooming effects in sky-sea atmosphere firstly. Then because laser weapons attack one target at a time and it takes several seconds at a minimum for the target engaged, a model of calculating the required t ime for damaging the attack target was built . In the end effective evaluation methods of hot-ablated and high-energy laser weapon’s damaging effectiveness are made, when the body or the optical elements of the missile is irradiated by the concatenation wave laser weapon. And one of the issues just as laser power, propagation distance is changed; the model can make different evaluation. The above model can provide the theoretical basis for the high-energy laser weapon intercept anti-ship missile and tactic deraign rationality for naval ship-borne laser weapons.

In this paper includes the superiority of analyzing of laser beam based on wavefront sensing in focal plane. It is introduced that two mainly basic principles of the technology of wavefront sensing. The correctness of this method is shown by the results of experiment. And the arrangement of experiment is simple. Experiment error is reduced easily. Application prospects and feasibility are proved sufficiently.

Illumination uniformity is one of the key specifications of lithography illumination system because of its strong influence on the critical dimension (CD) uniformity in optical lithography. Refractive microlens array (MLA) has been extensively adopted in lithography system to achieve highly homogeneous illumination field with less light loss relative to diffractive element. Off-line homogenization inspection of the MLA provides important data for entire system integration. It is still a challenge work to investigate the optical performance for such high-end MLA with large clear aperture and high sensitivity to the incident light parameters. In order to address these issues, subaperture stitching method has been proposed to be applied and studied in this work. The feasibility of this method has been verified by theoretical simulation of a diffracting homogenizer. In the experiment, a corresponding optical setup is constructed, and a crossed-cylindrical single-plate MLA has been tested. The experimental results are consistent with the simulation ones. It could be concluded that subaperture stitching method is a powerful method to evaluate the homogeneous performance of MLA.

This paper briefly introduces the commonly used photoelectric auto collimator structure and its working principle. A new method for calibrating the initial point of collimator CCD imagine by a pyramid prism was proposed. It consists of a two-dimension rotate instrument, a pyramid prism and a collimator. By combing with the algorithm of calculating the center position of beam spot, a more precise calibration of the initial point of the collimator CCD imagine was realized. Optical properties of the pyramid prism and its impact of initial point calibration were analysed under the oblique incidence. At the same time, effect of the manufacturing errors of pyramid prism on the calibration accuracy was analysed. Experimental data shows that the method has a good reproducibility with a relative standard deviation of less than 10%.

For the optical anti-reflection coating (ARC) and passivation properties, the relationship between parameters of PECVD and solar cell photoelectricity properties is investigated in this work. Solar cell’s photoelectricity properties are studied by using various optoelectronic measurement systems. It is found that minority carrier recombination can be reduced by changing the parameters of PECVD, specially tuning pressure parameter, and the hydrogen content is different as the gas total flow changing if the temperature and pressure no changes. And also the hydrogen content can be calculated by absorption spectrum being tested with optoelectronic measurement system.

Wave aberration of optical system describes the deviation of the exiting wavefront from perfect spherical wavefront. For field imaging, wave aberration of each field is generally different due to the existence of field-dependent aberrations induced by imperfect optical design and alignment. Wave aberration for different field is required to fully characterize the optical system. Wavefront interferometry and Shack-Hartmann wavefront sensing method are two traditional methods to measure the wave aberration. Compared to these two methods, image-based wavefront retrieval method determines wave aberration directly from image formed by the optical system with no extra hardware. This method has attracted more and more attentions for its unique advantages, and has been successfully applied in many domains such as large telescope alignment, X-ray imaging and so on. In this paper, we propose a spot image based multi-field wavefront retrieval method. As we know, wave aberration function of optical system is a function of the pupil and the field coordinates. Double Zernike expansion, which performs Zernike polynomials expansion on the pupil plane and image plane respectively, is used to fulfill field-dependent wave aberration expansion. With the coefficients of this expansion, wave aberration of every field can be obtained. The objective function and its gradient function for the multi-field wavefront retrieval are given and conjugate gradient algorithm is used to retrieve the coefficients of field-dependent wavefront expansion with the spot intensity images at different fields. Numerical simulation of this wavefront retrieval method is completed with MATLAB. The retrieval results are analyzed for both ideal and noisy conditions with different number of field points.

Time-of-flight measurement by using laser pulses is an alternative method in laser range finding and laser scanning, the echo pulses originating from backscattering of the emitted laser pulse on targets is detected by optical receiver. The distance of target can be obtained by measuring the round-trip time. Time-of-arrival estimation may be based on schemes such as constant-fraction discriminator (CFD) in analog electronics. In contrast, as sampled signals are available, time delay estimation may be based on schemes like direct cross-correlation function (CCF) and average square difference function (ASDF) in digital electronics. By the way, constant-fraction discriminator can also be used in digital electronics. All this three methods are analyzed and compared with each other. It is shown that estimators based on CCF and ASDF are more precise than conventional CFD based estimator.

A novel method for measuring droplet size and complex refractive index simultaneously using a CCD camera by rainbow detecting is proposed. A new mathematic model for rainbow pattern of absorbing droplet is built. Based on this model, a series of new formulas to measure droplet imaginary part of refractive index are derived. Then a new method for simultaneously measure droplet size and the complex refractive index is presented, which is verified by simulation experiments under different conditions. The experiment is performed to measure water with different dye concentrations. To avoid the effect of non-sphericity on refractive index detecting, a long and stable water cylinder instead of droplet is measured. Both the diameter and the complex refractive index of the liquid cylinder are detected by measuring the scattering rainbow light which is received by a linear CCD camera placed in the focus of the lens system. The result shows a satisfactory agreement with the theoretical analysis.

The direct substitution method is used in the laser beam widths meter (usually the laser beam profiler) calibration. The laser beam widths measurement results of device under test (DUT) are compared with those made by the laboratory standard. For most laser beam widths meter, the detector measurement plane is installed inside detector head, so it is difficult to accurately position the measurement plane for both standard and DUT. Depending on the ocular estimation, the difference of measurement plane between standard and DUT is usually controlled within 5mm. For 2.5mrad divergence angle of laser beam, 5mm tolerance will cause an uncertainty of 12.5μm in the beam widths measurement. In the optimized calibration system, a wedge prism placed in the beam path produces a precise beam deflection, which results in the laser spot displacement on the measurement plane. Depending on the measurable displacement of beam centroid position and the beam deflection angle, the distance from the wedge prism to the detector measurement plane is determined. The experimental results show that using the measurement plane positioning method, the difference of measurement plane between standard and DUT is close to 80μm, only contributing an uncertainty of 0.125μm in final result with the same 2.5mrad beam divergence angle. In additional, some factors affecting precisely positioning of measurement plane are analyzed in this paper.

Recently, ZWP grating diffraction imaging instrument has been applied in the research and teaching of bi-grating imaging effects by some universities. However, there are problems exposed in the use. The main problem is position location of bi-grating operation which hardly achieves the “Z” shape that is fit for imaging path, especially the diagonal direction deviation of the second grating when it is moving in the platform, which leads to measurement errors for the bi-grating diffraction imaging, and the experiment results are inaccurate. To the grating imaging instrument, the electronic control method has been studied, which is to control moving and rotation of gratings more easily and with high measurement accuracy. The new reform plan of the grating imaging instrument is done and tested, and the experiment results are compared with before reform undone.

An optical fibre laser characteristic measuring system is presented in this paper. Measurement parameters include laser linewidth, relative intensity noise (RIN) and output power. Homodyne analysis method is used to achieve linewidth which resolution of linewidth can reach 1kHz. Quantization noise of the RIN is decreased greatly. And RIN measuring lower limit reaches -120dB/Hz. Digital Potentiometer is adopted in the detection circuit to adapt to high range of laser power.

With the development of electronic technology in recent years, electronic components become increasingly miniaturized. At the same time a more accurate measurement method becomes indispensable. In the current measurement of nano-level, the Michelson interferometer with the laser diode is widely used, the method can measure the object accurately without touching the object. However it can't measure the step height that is larger than the half-wavelength. In this study, we improve the conventional Michelson interferometer by using a super luminescent diode and continuous wavelet transform, which can detect the time that maximizes the amplitude of the interference signal. We can accurately measure the surface-position of the object with this time. The method used in this experiment measured the step height of 20 microns.

We designed a measurement system to measure large size laser beam intensity distribution based on CCD diffuse transmission imaging. The measurement principle is presented. The configuration of the system is introduced. An emphasis is placed on the design of diffuse transmission target. The methods of spot geometry distortion correction and intensity distortion correction are described in detail. After laser spot correction, we can get the real laser beam intensity profile. The test results are given, which validate the correctness of the method. The paper provides a new way to measure quantitatively the profile of large size laser beam with high accuracy.