State Key Laboratory for Electronic Measurement Technology

Taiyuan, China

State Key Laboratory for Electronic Measurement Technology

Taiyuan, China
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Chen Y.,State Key Laboratory for Electronic Measurement Technology | Wang Z.,State Key Laboratory for Electronic Measurement Technology | Wang Z.,Key Laboratory of Instrumentation Science and Dynamic Measurement
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2014

Feature selection is an important part during the process of qualitative and quantitative analysis of infrared spectrum. In order to solve the disadvantage of traditional methods, such as multi-parameters, slow convergence, poor accuracy, prone to premature, etc., a novel feature selection algorithm was proposed, which combined the basic bat algorithm and Lévy flights search strategy. Meanwhile, due to the original version of bat algorithm was only suitbale for continuous problems, a binary version of bat algorithm was proposed. Three infrared spectrum datasets were used to check the performance of proposed method while the comparisons with traditional genetic algorithm, simulate anneal algorithm and uninformative variable elimination methods were also implemented. The experiment results show that, the proposed method can quickly find the global best combination of sub-intervals and improve the accuracy and stability of feature selection. More importantly, the selected wavenumbers have exactly physical meanings. Meanwhile, the generalized performance of the model established based on the selected wavenumbers was better than the whole spectral range. The tests on three different phases (solid, liquid and gas) and different spectral range indicated that, the proposed algorithm has a widely practical scope and value.


Zhang R.,State Key Laboratory For Electronic Measurement Technology | Zhang R.,Key Laboratory of Instrumentation Science & Dynamic Measurement | Wang Z.-B.,State Key Laboratory For Electronic Measurement Technology | Wang Z.-B.,Key Laboratory of Instrumentation Science & Dynamic Measurement | And 6 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2015

Existing Photoelastic Modulator (PEM), whose optical path difference (OPD) is small, has strict requirements on the incident spot size and is poor in the aspect of light use efficiency under multiple reflections. What's more, Photoelastic Modulator based Fourier transform spectrometer (PEM-FTS) spectral resolution is relatively poor. Because there are these disadvantages in the PEM, this paper presents a method of large optical path difference whose PEM is based on micro trapezoidal photoelastic crystals. By improving the structure of photoelastic crystal, the PEM becomes micro trapezoidal octagonal structure. And two transmission surfaces are changed slightly into a certain angle. Therefore, the PEM improved can not only increase the optical path difference of the PEM, but also have less requirements on the incident spot size. Firstly, a detailed analysis of the maximum modulation optical path difference was made in this paper. Secondly, the equation of maximum optical path difference was deduced under any angle and any position of incident light, vibration displacement and stress distribution of PEM are analyzed by the way of COMSOL Multiphysics 4.3a. Again, a method was analyzed to find the best angle of incidence, combining with maximum optical path difference and energy efficiency. Then the large OPD's PEM is designed and processed, including two parts: photoelastic crystal and piezoelectric crystal. Moreover, ZnSe crystal is used as photoelastic crystal, and piezoelectric quartz crystal is used as piezoelectric crystal. With experiment analyzed by 632.8 nm He-Ne laser, the results show that under the same driving voltage, the optical path difference of the PEM improved is about 19.25 times bigger than the normal PEM, and the relative error is 1.3%. ©, 2015, Science Press. All right reserved.


Zhang R.,State Key Laboratory for Electronic Measurement Technology | Zhang R.,Key Laboratory of Instrumentation Science & Dynamic Measurement | Zhang R.,North University of China | Wang Z.,State Key Laboratory for Electronic Measurement Technology | And 8 more authors.
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2015

Existing static wedge interferometer can not achieve zero optical path difference, thereby affecting the accuracy and speed of spectral inversion. Therefore, a method of achieving zero optical path difference by improving the wedge structure was put forward. By improving the structure of the inclined surface, the wedge can be achieved on the incident light interference signal which contains zero optical path difference. By deducing and analyzing the optical path difference of the arbitrary wedge position, and the formula of spectral inversion was deduced. Using Zinc Selenide (ZnSe) materials design and processing of the wedge, interference signal and the optical path difference was simulated, and the process of spectral inversion was simulated. The wedge was analyzed by experiments which used 10.64 μm laser. Result shows that the interference signal clarity, optical path difference can reach 1450 μm, and the relative error of experiment is 0.1%. ©, 2015, Chinese Society of Astronautics. All right reserved.


Zhang R.,State Key Laboratory For Electronic Measurement Technology | Zhang R.,Key Laboratory of Instrumentation Science & Dynamic Measurement | Zhang R.,North University of China | Wang Z.,State Key Laboratory For Electronic Measurement Technology | And 11 more authors.
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2015

Existing static wedge interferometer can not achieve zero optical path difference, and it requires a strict spatial coherence of light, thereby affecting the accuracy and complexity of spectral inversion. Therefore, a novel equivalent static wedge was proposed. It consists of two different refractive index material, and two reflective surfaces perfectly vertical. Because interference of two beams of light is derived from a beam of light, it is not strictly required about spatial coherence. Moreover, it contains zero optical path difference. By deducing and analyzing the optical path difference of the arbitrary wedge position, the formula of spectral inversion was deduced. Then the wedge was designed and processed by using two materials which were different refractive index, and its maximum optical path difference could reach 168.3 μm. And the process of spectral inversion was simulated. Combining maximum optical path difference with the measured spectral band, the requirement of the linear CCD pixel count was analyzed. The wedge was analyzed by experiments which use 532 nm and 632.8 nm lasers. The results show that the spectral inversion center wavelength error is less than 0.2%. ©, 2015, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.

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