Proceedings Volume 4223

Instruments for Optics and Optoelectronic Inspection and Control

Guang Hui Wei, Sheng Liu
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Proceedings Volume 4223

Instruments for Optics and Optoelectronic Inspection and Control

Guang Hui Wei, Sheng Liu
View the digital version of this volume at SPIE Digital Libarary.

Volume Details

Date Published: 5 October 2000
Contents: 1 Sessions, 62 Papers, 0 Presentations
Conference: Optics and Optoelectronic Inspection and Control: Techniques, Applications, and Instruments 2000
Volume Number: 4223

Table of Contents

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Table of Contents

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Papers
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Coherent 1.06-um cw laser radar system
Su Hui Yang, Ke Ying Wu, Chang Ming Zhao, et al.
A coherent 1.06micrometers all solid state laser radar system is proposed. The system uses a LD pumped monolithic Nd:YAG ring laser as the source. Very stable output of the laser is linearly frequency modulated by an acousto-optic modulator. The wide modulation bandwidth is achieved by cascading two Bragg cells, in which each cell produces half of the total bandwidth. In order to extinguish the laser beam deflection caused by the Bragg cell, the propagation directions for the acoustic waves are arranged to be opposite in the two cells. Two single model optical fiber couplers are utilized. One is used as a beam splitter and divides the modulated laser beam into two parts: the transmitted signal beam and the local reference beam. The other coupler mixes the target-reflected signal beam with the local reference beam. The output signal form this coupler is detected by an InGaAs PIN photodiode, then analyzed by a RF electronic spectrum analyzer. The linearly frequency modulated CW ladar system can be applied for measuring both range and velocity of the target. Using this ladar system, true 3D target imaging can be achieved by additional use of a laser beam-scanning device.
Nonplanar ring laser with the corner cube prism
Ke Ying Wu, Su Hui Yang, Chang Ming Zhao, et al.
Kane and Byer reported the first monolithic non-planar miniature ring laser in 1985. An intrinsic optical diode enforces unidirectional and hence single-frequency oscillation of this device. We put forward another kind of the non-planar ring lasers, in which the corner cube prism is the eye element. The non-planar traveling ray in the corner cube, Faraday rotation in the Nd:YAG crystal placed in a magnetic field and the different output coupling in S and P polarization can yield the single-frequency laser output in theory. The distorted Porro prism made by Nd:YAG crystal plays the role of the laser medium and the laser output coupler is realized by one of the two roof surfaces. The whole system can be made as a quasi-monolithic laser by optical bonding technology.
Measurer for polarization of PM fiber
Jun He, HongJie Xu, BingKun Qin
In the article, a novel device used for measuring the polarization of the PM fiber is introduced. GRI lenses are used to take the place of microscopic objectives in it. In order to get higher extinction ratio, the characters of Gauss-light are referred and coupling efficiency of the system is also analyzed. To validate, experimental data are given.
Deformation measurement of high-power laser resonator mirrors using 2D shearing interferometer
Lei Fu, Hongmin Shi, Shouyong Ni, et al.
An optical layout of a common optical-path shearing interferometer is proposed in this paper. Research on the heated deformation of high power laser resonator mirrors with the 2D shearing interferometer is presented. The experiment demonstrates the method feasible and reliable in investigating the heated deformation.
Laser fluorescence for the detection of oil pollutants in the environment
Yi He, Jixiang Yan, Jiaze Li, et al.
A laboratory unit is described that was designed to detect and identify the oil pollutants in the environment by means of the laser-induced fluorescence spectrum analyzer. UV laser beam from third harmonics of the Nd:YAG laser is used to excite target oil. The multichannel detection system consists of a spectrometer, a scientific-grade gated ICCD camera and a digital delay generator. A personal computer is responsible for the control for the whole system as well as for the data processing. In the experiment, the laser beam is directed toward the samples while the return fluorescence signals is collected by a Cassegrainian reflecting telescope. The received signals pass through a bunch of fibers, and go into the input slit of the spectrometer. The fiber bunch includes 19 fibers, one end of which take shape of disc to collect the signals from the telescope while the other arrange in a row to match the spectrometer slit. As the results, the fluorescence emitting spectrum of sample oil under the illumination of laser beam wavelength of 355nm is in the range 400nm to 700nm and center around 520nm. The laser and the receive system are both at a distance 25m from the target since the restriction of the working place. The system has the detection capacity for more distance.
Improvement of tapping-mode scanning near-field optical microscope
Wenjiang Zhuo, Qin Li, Jialin Sun, et al.
The commercial crystal tuning fork glued with an optical fiber probe is used as the sensitive detecting element for the tapping-mode scanning near-field optical microscopy. Firstly, the single-mode optical fiber is etched down to a small diameter to decrease the burden of the tuning fork. Secondary, the fiber is etched for the second time to form the sharp tip with large cone angle. Thirdly, the fiber probe, with nanometric tip and high light throughput, is glued to tuning fork by Cyanoacrylate Adhesive. The measured quality factor, Q, of the tuning fork/optical fiber probe assembly prepared in this way is higher than 300. The optical signal is modulated to the frequency of the tuning fork by optical fiber probe as it is detecting the topography of sample. The high-resolution of the tapping- mode detector is proved by imaging the topography of the grating and biological cell.
Design of a flat-field miniature spectrometer
Daoyi Wang, Guofan Jin, Yingbai Yan, et al.
A method of designing a flat-field planar concave grating for a miniature spectrometer is studied based on the second- order aberration is defocusing. To obtain low defocusing, two steps are applied: first tune the detecting plane, then adjust the groove distribution.
Full autonomous microline trace robot
Deer Yi, Si Lu, Yingbai Yan, et al.
Optoelectric inspection may find applications in robotic system. In micro robotic system, smaller optoelectric inspection system is preferred. However, as miniaturizing the size of the robot, the number of the optoelectric detector becomes lack. And lack of the information makes the micro robot difficult to acquire its status. In our lab, a micro line trace robot has been designed, which autonomous acts based on its optoelectric detection. It has been programmed to follow a black line printed on the white colored ground. Besides the optoelectric inspection, logical algorithm in the microprocessor is also important. In this paper, we propose a simply logical algorithm to realize robot's intelligence. The robot's intelligence is based on a AT89C2051 microcontroller which controls its movement. The technical details of the micro robot are as follow: dimension: 30mm*25mm*35*mm; velocity: 60mm/s.
In-situ measurements of large external diameters by a heterodyne laser interferometer
Qibo Feng, Jinwen Liang
A laser heterodyne interferometer has been widely used for a long time in industry, and it has advantages of both large measurement range and high accuracy. SO, how to directly use this highly precise laser interferometer for measuring dimensions of large-scale workpieces, especially large diameters, is a target to b pursued. Due to the difficulties of aiming at and positioning the measured points in the measurements of large workpieces, this problem has not been solved up to now. Here, a novel and very simple method of aiming at and positioning the measured points in the dimension measurement of a large-scale workpiece by a single laser beam is put forward, and high-precision measurements of large dimensions can be realized by a commercial available laser heterodyne interferometer. High accuracy, large measurement range and convenience of operation are some distinguishing features of this method. The experiment results on both a 1000mm-gauge block and a 500mm-diameter shoed that the uncertainty within 5 micrometers in measuring a one meter diameter was obtained by the system.
Design of fly's eye homogenizer for excimer laser micromachining
Tiechuan Zuo, Tao Chen, Chengde Li
In this paper, the design of a fly's eye homogenizer for excimer laser micro-machining is described. The homogenizer has high performance in averaging the strong intensity fluctuations of the incident excimer laser beam and low transmitting loss. The dimension of the output beam can be adjusted continuously.
High-power laser beam and focus transverse intensity distribution measuring instrument
Qiang Li, Hong Lei, Tiechuan Zuo
Using the method of rotating hollow probe, the measuring system which can directly measure laser transverse intensity distribution of high power laser beams/focus for laser processing is studied. The mathematical and physical models of measured laser beams/focus propagation in hollow probe are founded. According to the calculation, the system parameters, including pinhole diameter of hollow probe, dimension of propagation channel, dot number of sampling, are discussed. A new measuring system is designed. The measuring of high power laser beams/focus by this system is realized. The calculation results are satisfied with the measuring results. The instrument can measure CO2 and YAG laser, measured power larger than 10kW, maximal measured power density up to 107w/cm2, maximal diameter 60mm, laser focus minimal diameter smaller than 0.5mm.
Thermal effect of high-power laser and output laser beam quality
Peihua Lu, Runwen Wang
In this paper, thermal equation of high power laser output coupler is established, and analysis solution of the equation with its boundary value of the actual model is given. The temperature distribution of output coupler is obtained. Then the thermal lens of output coupler is calculated also. Otherwise, the beam quality of output laser is discussed. All of these problems are significant for high power laser design.
Second and third harmonic generation in quasi-phase-matched annealed proton-exchanged lithium niobate waveguides
Xianfeng Chen, YuXing Xia, Shengwu Xie, et al.
Waveguide quasi-phase-matched second-harmonic generation devices are being studied as a promising candidate for realization of a compact short wavelength coherent light source. In this paper, we report quasi-phase-matched second harmonic generation (SHG) in proton-exchanged (PE) lithium niobate waveguide with the fundamental wavelength of 1300nm. The domain inversion was obtained by Ti-indiffusion method near Cuire temperature. The waveguide was fabricated by proton-exchange in the melting benzonic acid, followed by annealing in the air. SHG efficiency as high as 22 percent was observed in the 5mm long periodically pulsed PE lithium niobate waveguide. The SHG conversion efficiency as a function of the fundamental wavelength was measured which exhibits good agreement with the theoretical study. We also found the third harmonic generation from the QPM PE waveguide caused by the cascading nonlinear optical procedures including SHG and sum frequency generation.
CVD diamond micro hinge for MOEMS applications
Guifu Ding, Xiaolin Zhao, Xiang Yao, et al.
CVD diamond films is one of the most interesting materials under consideration for microelectromechanical system (MEMS), especially for optical MEMS, but diamond is difficult to be fabricated due to its hardness and chemical inertness, for this purpose, we have developed a patterning process based on O2RIE etching of CVD diamond films and formed a new type of surface micromachining process for microfabricating of diamond MOEMS microparts, combining with sacrificial releasing and electroplating through mask techniques, this surface micromachining process is able to fabricate fine lines and complicated microstructures, and a diamond micro hinge for free-space micro-optical bench has been fabricated by this process successfully.
First-order quasi-phase-matched second harmonic generation in bulk periodically poled LiNbO3
A first order quasi phase matched periodically poled LiNbO3 for SHG with 6.5 micrometers period, 10-mm length and 0.5-mm thickness has been successfully fabricated by applying an external electric field with an optimum high pulsec voltage generator. About 18-mW of cw 0.532 micrometers green light was obtained pumped by a 1.1 W of cw 1.064 μm Nd:YAG laser with end coupling, which corresponds to 1.6 percent power conversion efficiency. The SHG normalized conversion is about 1.5 percent cm-1W-1, which shows 79 percent of the ideal nonlinear coefficient.
Calibrated equipment for return loss of fiber optic passive components
Limeng Wang, Yongsheng Wu, Xuhui Luo
We report a calibrated equipment for return loss (RL) of fiber optic passive components, the expanded uncertainty for this equipment are 0.80dB(0--60)dB, 1.60dB(-60- -70)dB with 1300 nm and 1550 nm wavelength, RL measurement repeatability to 0.25dB(--60)dB, 0.50dB(-60--70)dB, and stability to 0.20dB(0- -60)dB, 0.40dB(-60--70)dB are obtained by experiments.
All-fiber optical measurer of mineral oil in water based on three-dimensional fluorescent light spectra
Shuqing Zhang, Jinshan Shi
In this paper, the parameter quantification principle of 3D fluorescent light spectra and its realization technique are studied. The portable all fiber-optical fluorescent light measurer of mineral oil is given too. It can measure the qualified data of the content of the mineral oil in water quickly and really, and dispense of any chemical reagent.
Novel F-P dual interferometer for measuring small displacement
An optical fiber dual-interferometer for measuring small displacement has been developed in this paper. A wavelength- scanning source is used to simultaneously illuminate two Fabry-Perot cavities. One is as the sensing cavity, the other is as the reference cavity. If the length of the reference cavity is pre-calibrated and maintain constant, and the scanning wavelength is taken as an inter-converter to compare the gap length of the sensing cavity with the reference cavity length, using the frequency spectrum separator, absolute measurement can be obtained.
High stability and output energy of optical parametric oscillator by square pulse laser pumped
Li Wang, Yu Zhao, Liu Huang
A high stability and output energy of wide band tunable intelligence optical parametric oscillator is developed by which square pulse YAG laser in temporal domain pumped. By means of the smooth cavity dumping, the reduction of output loss compensates the photon decrease in cavity. In experiment, we have investigated energy conversion efficiency to compare the Gaussian pulse with square pulse and obtained the 16.5 percent to 34.5 percent energy conversion efficiency of the optical parametric oscillator by the square pulse pumped.
GaAs optical fiber temperature sensor
Junliang Zhao, Rongfeng Guan, Hongtu Zhao
This paper, based on establishing the mathematical model of GaAs optical fiber temperature sensor, studies the effect of light source spectrum on the properties of sensor from computer simulation and experiment aspects.
Numerical simulation of photoelectric characteristic of three-channel bulk charge-coupled device in the x-ray region
Min Song, Yuxin Wang
In this paper the photoelectric characteristics of the three-channel bulk charge-coupled device (BCCD) was simulated in the region of x-ray. The results show that the silicon three-channel BCCD can not work in the region of x- ray because of improper absorption coefficient of silicon. The absorption coefficient curve of a new material is given in this paper. By using the absorption coefficient of the new material, three maxim positions of the spectral photosensitivity are obtained at 1.8kev, 1.2kev and 0.6kev, respectively.
Photoelectric detection system of inside flaws of metal tube
This paper introduces a photoelectric detection system, i.e. the internal surface of the metal tube illuminated by Xenon light through fiber bundle, is imaged on CCD optical receiver by endoscope. The image can be converted to video frequency signal, then this signal can be converted to digital signal by a sampling control system, which processed by a computer. SO the measurement system can clearly display the surface flaws of workspace of complicated construction, and quantitatively measure sorts of flaws by an image processing system.
Effective medium theory for designing binary circular subwavelength diffractive optical elements
Caihua Chen, Zhenwu Lu, Baochang Zhao
A procedure for design binary circular subwavelength diffractive optical elements (DOE) is presented. In this procedure, we first generalized the design approach presented by Farn and extend Farn's techniques to include the design of binary circular subwavelength diffractive optical elements, we apply the zeroth-order effective medium theory in every subwavelength area to determine the relationship between index and the fill factor. An example is presented. The body of revolution finite difference time domain method is used to analyze responses of this DOE. The results are compared with the counterparts of its continuous profile.
New type of micropump using SMA thin film actuator
Tongyu Wang, Huilin Jiang
In this paper, a new prototype model of a micropump using a SMA thin film actuator as the servo actuator is proposed. This micropump consist of two one-way valves that make use of the same SMA thin film actuator. The overall size of this micropump prototype is 12mm in diameter and 20mm in length. The characteristics of the micropump were measured, experimental results indicating that the micropump provides satisfactory responses.
Microgripper using an ICPF actuator
Tongyu Wang, Huilin Jiang
In this paper, a new prototype model of microgripper using an ICPF actuator as the servo actuator is proposed. The ICPF actuator is made form the film of perfluorosulfonic acid polymer, chemically plated on both sides with platinum. This paper describes the new structure, the motion mechanism and characteristic measurement of a microgripper using an ICPF actuator.
Photoelectric soft x-ray multilayer coating thickness control system
Xuan Ming, Bin Chen, Zhi Liu
This paper introduces a photoelectric soft x-ray multi-layer thickness control system. This paper highlights the operating principle of ion beam sputter coating system, the hardware and software scheme of coating thickness auto- control system.
Potassium Faraday optical filter in line-center operation at 766 nm
Xiaoling Jia, Yundong Zhang, Yong Bi, et al.
In this paper we investigated potassium Faraday filter at 766 nm theoretically and experimentally. With a potassium cell of 0.01m in length in an axial magnetic field of 0.0815T, the line-center operation has been achieved. The calculated peak transmission has reached 83 percent with a FWHM bandwidth of only 1.5GHz, the measured FWHM bandwidth of the filter is 1.6GHz, which is in good agreement with the theoretical result.
Theoretical and experimental study of Cs 852-nm FADOF
Yong Bi, Yundong Zhang, Xiaoling Jia, et al.
In this paper, the theoretical model and experimental demonstration of Cs 852nm FADOF in weak and strong magnetic field are discussed. Whenthe FADOF system working under the weak field, the theoretical and experimental results are agreement with the previous repot. In the case of strong field, when performing condition is B equals 0.0883T, T equals 351K, the line-center operation is observed. The comparison between the theory and the experiment gives reasonably expected results.
Novel pressure sensor with a Fabry-Perot interferometer
Zhiquan Li, Lina Fan, Xifu Qiang
A novel pressure sensor using a fiber Fabry-Perot interferometer (FFPI) has been developed in this paper. We use the internal F-P cavity pressure sensor in our research. Micromachined Fabry-Perot microcavity structures have been investigated for use as a pressure sensor. The single-mode fiber containing the interferometer is bonded at one end to the stainless-steel diaphragm and is also attached under longitudinal tension beyond the interferometer. An analysis relating the expected interferometer phase change to pressure is presented. And the dynamic response of FFPI sensor to pressure changes produced by an air pump is in good agreement with that measured with a conventional pressure sensor. The sensor is suitable for operation with other signal-processing and multiplexing schemes.
Fiber Bragg grating strain sensor with drift compensation for smart structures
Zhiquan Li, Zhibin Wang, Xuhui Tang, et al.
In this paper, Fiber Bragg grating sensor is studied and aline linear relationship between phase difference and strain is achieved. A Fabry-Perot interferometer is used to select a specific wavelength and a reference channel is introduced to compensate for random phase drifts, improve the sensitivity and the resolution.
Grating angular displacement transducer using a Fabry-Perot structure and its performance improvement
Zhiquan Li, Xifu Qiang, Zhaoxia Wu, et al.
The Fabry-Perot interferometer (FPI) has been traditionally used to examine either small spectral ranges or relatively simple spectra. Recently, however, the studies have shown that the FPI can be competitive with the Michelson interferometer over extended spectral ranges. A relatively new FPI is described based on two gratings. In order to measure angular micro-displacement, a novel grating angular displacement transducer using a multiplex Fabry-Perot interference technology has been developed in this paper.
Neural fuzzy network applied in fire detection system
Zhiquan Li, Chunling Fan, Lingshi Yao, et al.
A neural-fuzzy network applied in fire detection system is presented in this paper. New Back-Propagation algorithm with optimization-based architecture revised automatically is proposed to train network structure. Experimental results show this system can detect china standard experimental fire correctly and lower false alarm.
Sensitive intracavity photoacoustic spectrometer based on CO2 waveguide laser
Shaocheng Li, Qingxu Yu, Zhibin Chen, et al.
Photoacoustic spectroscopy (PAS) is a promising spectroscopic technology due to its intrinsically high sensitivity, large dynamic range and comparatively simple experimental arrangement. In this paper a photoacoustic interactive configuration is presented. The system consists of three main parts: CO2 waveguide laser, a photoacoustic cell and electronic measurement system. The resonant photoacoustic cell excited in its first longitudinal mode is placed inside the optical cavity of the CO2 waveguide laser. Due to the high intracavity power the photoacoustic signal is enhanced almost tow orders of magnitude compared with the extracavity configuration. The optimum system design was found by numerical simulation of the acoustic properties of various cell geometries. An open- resonator model is developed and analyzed in detail. The characteristics of the system we have predicted using the theory match the experimental results very well. Many methods such as adding iris before the spectrometer, adjusting the position of chopper are used to modify the configuration of the system, which proved to be helpful to get better quality. A computer program based on spectroscopic tack technique system improves the long-term stability and measurement accuracy. Finally this PAS system is applied to various trace gas analysis of plant successfully and a detection sensitivity of ppt level for C2H4 is reached.
Succinct design method of soft x-ray multilayer mirror
In order to acquire high reflectance, how to select the thickness dH and dL of the high and low atomic numbers materials should be considered first of all in the design of soft x-ray multi-layer. This paper introduced a simple design method based on matrix method. In the design process of a multi-layer mirror using Mo/Si at (lambda) equals 13.1 nm and normal incidence, its reflectance reaches 67.0 percent when layers are 30. Compared with other method, although its reflectance is a bit lower, it is a simple and practical method.
Wavelength measurement using dual photodetectors
Xiaodong Zeng, Shubin Wu, Yuying An
Based on the fact that the Si and InGaAs photodiodes have different spectral response curves, a new method for measuring the wavelength of laser beams is proposed. It is shown that this method is simple and reliable. The spectral resolution could be +/- 10 nm.
Analysis of mechanism for the operational mode of lock-on in PCSSs
Renxi Gong, Yimen Zhang, Shunxiang Shi, et al.
An experimental and theoretical investigation of PCSS's behaviors has been performed with emphasis on 'lock-on' is intimately related to bias voltage, triggering optical energy and the concentration of deep energy level trap in PCSS's by 2D simulation with MEDICI. This effect is observed only when the three factors all satisfy corresponding threshold values that vary with operational conditions. The reason is that under such condition, the distributions of the electric field, potential, carriers and current densities in PCSS's can be notably changed, the accumulation of carriers will be formed and electric field will be gradually enhanced in some region. It ultimately reaches the critical electric field for avalanche ionization, thus avalanche multiplication of carriers occurs.
Photoluminescence spectrum measurement of GaAs photocathode material
Hui Guo, Vitaly Pravdivtsev
The luminescence generation mechanism of semiconductor epitaxial structure and the basic principle of photoluminescence spectrum measuring instrument are outlined in this paper. Detailed method about how to make use of the instrument to measure the doping level and composition as well as the uniformity of GaAs/GaAlAs layer is described. In the end, the effect of these parameters on the function of the III-gen photocathode is discussed.
Valid methods for improving reliability of the MPU-controlled YAG laser
Zhihong Liu, Dan Zhu, Wensheng Guo
It is important for the MPU controlled YAG laser to work reliably because those unexpected laser pulses can do operators harm. In present paper, valid methods including hardware and software developments are described to improve the reliability of the MPU controlled YAG laser. The experiments show that, by using developments of the hardware and software, the MPU controlled YAG laser can work reliably even in the strong electromagnetic disturbance field.
Performance and application analysis of 8- to 12-um IR-CRT scene simulator
Huisong Jin, Youshen Lin, Shiyue Wang, et al.
The inspection of IR guided weapon system require an IR scene simulator that can display real-time, dynamic, and controlled IR images to simulate the target and background of battlefields. IR-CRT is one of these prominent simulator technologies. This paper describes the characteristics of 8- 12 micrometers IR-CRT simulator. The imaging performances, parameter measurements and applications are analyzed.
Image enhancement and 2D-TDI technique of infrared system
Chun Lei, Baomin Zhang
2D-TDI technique usually be used to improve SNR of IR system, but the effect is not obvious when the delay time is not long enough. Several IR image enhancement method based on 2D-TDI using gray transform has been put forward in this article. Testing results show these methods are superior to simple average method and can be implemented in real-time thoroughly. So they have high practical value.
3D test and analysis sytem on time-space SNR of low-light-level (LLL) CCD camera
Noise property is one of the main properties of LLL CCD camera. It indicates the limited detection ability of LLL camera. At present test and analysis technique on noise of LLL camera plays a very important role in the area of night vision technology. In this paper, taking the LLL CCD camera, which our research laboratory developed as the object of study, a novel method, 3D test and analysis technique on time-space SNR of LLL camera, is put forward. By using image board as signal sampling device, through the close coordination of electronic computer and image board in hardware linkage and software programming, the LLL camera 3D SNR test and analysis system is set up. Using this system, the 3D time-space SNR of the LLL CCD camera, which our research laboratory developed is tested and analyzed successfully.
Detecting and evaluating the viewing-angle characteristic for LCDs at different conditions
ZhongAn Liu
The method of evaluating and detecting the viewing-angle characteristic for LCDs with effective operation voltage range is introduced in this paper. This method not only can briefly evaluating and detecting the viewing-angle characteristic for LCDs with one parameter at different condition, but also can optimizing the operation voltage of LCDs.
Method of measuring electricoptical parameters for LCD modules
ZhongAn Liu
In this paper, the method of measuring electric-optical parameters by controlling operating voltage in LCD modules is introduced and discussed, luminosity-compared method for measuring electric-optical parameters of LCD modules is put forward farther.
Design of a compact multichannel spectrophotometer using a holographic concave grating as dispersive element
Jiwu Chen, Wei Wang, Zhineng Li
This paper presents design of a multichannel spectrophotometer, which uses a holographic concave grating as dispersive element. The flat spectral field of the grating generates the integration of collimation, disperse and convergence. Meanwhile, a CCD with 2048 pixels is placed on the spectral plane as a multichannel photodetectors so that the system can eliminate mechanical scanning. Due to the features of those elements and design procedure, the spectrophotometer shows more advantages that the structure of the new typed spectrometer becomes smaller, its stability, reproducibility and the rate of measurement have been much more increased.
Dynamic data processing and real-time modeling based on optical detecting
Bing Ye, Yetai Fei, Yonghong Wang
The modeling and prediction of dynamic measurement error are based on the analysis of the dynamic system and processing methods of dynamic data. In this paper based on theory of fuzzy clustering, fuzzy diagnose and fuzzy neural network and the circular optical grating angle measuring system used as an example, the prediction model of dynamic real-time measuring error is then set up. With the formal work results the dynamic fuzzy reliability of this prediction system has been analyzed in order to give the effectiveness of the model.
Analysis of trace organic compounds in vehicle emission using REMPI/TOF-MS
Ziyao Li, Jie Wei, Zhuhong Xia, et al.
Emission of fuel combustion in vehicle engines is one of the most important sources of urban environmental pollution. In this paper we present a new method for detecting trace pollution gases of vehicle emissions - laser mass spectrometry. The principles of the laser mass spectrometry is combination of resonant enhanced multiphoton ionization with flight-of-time mass spectroscopy. The experimental setup and results on the exhaust gas of a motorcycle are detailed. By excitation of 248nm KrF excimer laser, benzene and other aromatic compounds are detected in the motorcycle exhaust gases. The preliminary results of the concentration change of these compounds with speed are also presented.
La-implanted Si-based emitting film materials
Meiling Yuan, Qingnian Wang, Yuxin Zeng, et al.
The photoluminescence (PL) spectra at room temperature for monocrystal Si wafer thermal oxide Si samples doped by La ion implantation are measured. The results show that all the samples possess blue-violet photoluminescence properties under the UV light excitation and its light emission is stable. The intensity of PL peaks increases with the increasing of La ion dose during ion beam synthesis within a certain limits. Moreover, PL is closely related to the temperature of rapid thermal annealing. Besides, the feature and appearance of the samples was surveyed, with atomic force microscopy. The photoluminescence mechanisms for our samples is also discussed.
Signal handling in the use of CCD in multichannel spectral detection
When CCD is used in multichannel spectral detector, it is output accompanied with noises and distortion because of the device working in the condition of lower lighting, and because of the sensitivity of CCD different from the wavelength. The paper is focused on how to get a good signal by clearing up the signal out from CCD.
Novel instrument for ultraprecise measurement of diameter
Zhifeng Chen, Haibao Lu, Shaozong Zhang
A novel instrument that can attain ultra-precision for measuring diameter of both orifice and cylinder is presented in this paper. The instrument is based on a combination of blazed grating, air-lubricated hydrostatic slide guide and ruby probe. The measure method is touch absolute measurement. Air-lubricated hydrostatic slide guide is adopted here to guarantee straightness. The blazed grating and ruby probe are applied to assure high resolution of Edge-checkout and length measurement. Meanwhile, the measurement force control system is controlled by electromagnetism so that the touch force between workpiece and ruby probe can be decreased. Therefore, the transform of the testing workpiece, which caused by touch force is decreased. The way of testing temperature control and vibration control is also used to ensure system high accuracy and measurement repeatability.
Software solutions to quality enhancement of moire fringes in displacement measuring
Shaojing Su, Zhiping Huang, Haibao Lu, et al.
To acquire high precision of subdivision in optical displacement measuring, the signal quality of moire fringes must be kept reliable and constant. Several software solutions to enhance the signal quality of moire fringes are provided in this paper. The process platform is based on SHARC DSP and flash sample technique. Three methods of adaptive digital filter are used respectively to eliminate the unwanted drift of signal, improve the orthogonality of two channels of sine and cosine intensity signals of moire fringe, and keep the amplitude of the signal constant. Firstly, the operation procedure of the acquisition and process system is described, then the principle of the adaptive signal process is explained. And at the same time, the result of the experiment is also listed to show the effects of the process software in digital signal processor.
Modulation transfer function testing of FPA using narrow-band laser speckle
Qing Hua, Wenlong Zheng, Yuguang Li, et al.
This paper shows an approach using tunable narrowband speckle pattern generated by a double-slit aperture laid behind a new microcrystalline glass material scattering screen, for testing MTF of FPA between zero and twice Nyquist frequency. The measurement near to the Nyquist frequency, this method proved highly effective much better than that obtained by the Wide-band Laser Speckle.
Detecting the transmutation of car interwheel during the process of experimental braking with CCD camera
Saixian He, Duiyan He, Sidong Zhong
The paper discusses the way to get the degree of the transmutation of the car inter-steel-wheel by the heat during the process of braking. The principle and experiment of the measurement system is given out. The main factors that affect the measurement have been analyzed in theory and experiment. The method to describing the shape shifting of the car inter-steel-wheel is discussed.
Theory and practice of establishing optical fiber baseline field
Saixian He, Sidong Zhong, Mozhi Yu
In this paper an exploratory study of establishing an optical-fiber base-line field, which can take the place of the old outdoors base-line field that is used to check and calibrate the range finder, is presented. A reasonable method to use Optical fiber as the length standard has been put forward, the main factors which affect the precision of the optical path length when the light transmits in the optical fiber are analyzed in theory and experiment. Some problems on establishing an optical-fiber base-line field to check and calibrate the range finder have been discussed. The experimental result is given out, which shows that it is possible to establish the indoors optical base-line field either in theory or in practice.
Method of measuring the necking in material tensile test
Yan Sun, Guohua Cao, Li Li
This paper puts forward a new method of optical non-contact measurement in the necking process of material tensile test. By the scanning of polygonal prism and the linear array CCD we can measure the whole dynamical process, which includes the change of the necking position and the necking quantity with the gradually applied load. The results prove that this method makes the mechanical property of material described more accurately and the use of material more optimization.
Measurement of object lidar scatter image character
Yi Gao, Shu Gao
This paper introduces the methods used in the measuring extracting of the character of object lidar scatter image. They are the bases of lidar object recognition and the design, use and performance evaluation of laser weapon systems. Besides, the paper also analyzes the influence on the measurement of lidar scatter intensity by Speckle noise, which can be eliminated with correlation filtering.
Laser-heating and fuse-permeating research of coat tools' surface
Weina Liu, Ping Chen, Ling Chen
To prevent the surface of coat tools from eroding and improve the longevity of coat tools, the laser-heating and fuse-permeating process, a method which adopt high-power acute laser scan for W18Cr4V steel and for micron spraying WC tools to acquire the alloy-coating, get fusing or nonfusing of tools further surface, however, a fuse- permeating layer is formed between the further surface and original body, then quickly-cooled to concord with some property. According to the experiment of laser-phased harden layer atom distribution. Atom W has the obvious diffusing tendency to the original body, the thickness of the fuse- permeating layer >= 20 micrometers , and the crystal particle is small. All this get high performance to decrease the fracture which extend along crystal side.
Lapping metal mirror at high speed
Chunlin Tian, Jingfeng Fan, Weibing Wang, et al.
This paper discusses lapping a metal mirror with solid abrasives at high speed. In this method there are three procedures. First the workpiece is ground in a grinding machine, which makes the surface roughness of the workpiece reach about Ra1.6micrometers . Second the workpiece is lapped roughly on a lapping machine, which makes the surface roughness of the workpiece reach about 0.1micrometers . Last the workpiece is lapped finely, which makes the surface roughness of the workpiece reach about Ra1nm. Because solid abrasives are used, the machining efficiency is very high. Each lapping procedure time is only about one minute. A high speed, high efficiency and accuracy machining is realized.
Design of optical waveguides with new silicone-based polymers
Qiong Xie, Zhene Xu
Single-mode optical waveguides have ben fabricated form the silicon-based polymer with good transparency in this paper. The waveguides with novel structure can be easily processing by the common spin coating technique. These waveguides have high thermal stability because of high temperature curing. In addition, they can operate in single mode and have lower optical losses.
Feature extraction in character recognition with a neural network
Ping Li, Xiaofeng Mu
Neural net is capable to recognize handwritten characters and the keg of is the extraction of features if the pattern feature do not include enough information of feature recognition objects or cannot extract the structure information reflecting the object feature, they can not be recognized therefore, the rapid and effective extraction of the features which reflect the structure information of objects is the key of pattern recognition due to joining script and separate script, handwritten characters are the problem of segmentation. Segmentation is the initial problem of recognition this paper purposes the adoption of measures, such as fuzzy set theory membership function, improved character segmentation the feature extraction of uneven net density, to accomplish the segmentation the feature extraction of uneven net density, to accomplish the segmentation of characters and the feature extraction, thus to increase the recognition rate of characters.
Miniature blackbody radiation source
Songming Li, Rongpu Xu
The miniature blackbody radiation source is a kind of very small IR radiation source. It is mainly used to simulate moving IR targets. It is one of the key component parts of IR missile test stations. Because of its very small dimension, it is very difficult to develop. This article reports our technical project of the miniature blackbody radiation source. The final testing result same also presented in the end.
Compensation of phase change upon reflection in white light interferometry
Min-Cheol Park, Seung-Woo Kim
In this paper we present a compensation method of the phase change upon reflection with a particular aim of measuring step heights using white light interferometry.
Generation of complicated arrays by multiple beam interference
Alika Khare, P. Senthikumaran
We report the generation of 2D hexagonal array geometry of equally illuminating light spots using the interference of eight beam. Geometry and size of the arrays can be easily controlled by appropriate orientation of the optical components in the reported configuration.