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Advanced astigmatism-corrected tandem Wadsworth mounting for small-scale spectral broadband imaging spectrometer (EI CONFERENCE) 会议论文
Lei Y.; Lin G.-Y.
收藏  |  浏览/下载:29/0  |  提交时间:2013/03/25
Tandem gratings of double-dispersion mount make it possible to design an imaging spectrometer for the weak light observation with high spatial resolution  high spectral resolution  and high optical transmission efficiency. The traditional tandem Wadsworth mounting is originally designed to match the coaxial telescope and large-scale imaging spectrometer. When it is used to connect the off-axis telescope such as off-axis parabolic mirror  it presents lower imaging quality than to connect the coaxial telescope. It may also introduce interference among the detector and the optical elements as it is applied to the short focal length and small-scale spectrometer in a close volume by satellite. An advanced tandem Wadsworth mounting has been investigated to deal with the situation. The Wadsworth astigmatism-corrected mounting condition for which is expressed as the distance between the second concave grating and the imaging plane is calculated. Then the optimum arrangement for the first plane grating and the second concave grating  which make the anterior Wadsworth condition fulfilling each wavelength  is analyzed by the geometric and first order differential calculation. These two arrangements comprise the advanced Wadsworth mounting condition. The spectral resolution has also been calculated by these conditions. An example designed by the optimum theory proves that the advanced tandem Wadsworth mounting performs excellently in spectral broadband. 2012 Optical Society of America.  
Study on spectrograph for ionosphere: A broadband imaging instrument prototype for far-ultraviolet (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2011: Space Exploration Technologies and Applications, May 24, 2011 - May 26, 2011, Beijing, China
Yu L.; Wang S.-R.; Lin G.-Y.
收藏  |  浏览/下载:20/0  |  提交时间:2013/03/25
Current research on space-based exploration for the ionosphere needs more advanced technologies. Because the spectral signals in the ionosphere distributing basically in the far-ultraviolet waveband are very weak. Usual spectrometer structures and detectors such as CCD can't receive enough information. Based on this principle of atmospheric sounding  the imaging spectrometer prototype for ionosphere detection application was designed to solve the problem. This prototype consists of the telescope and the imaging spectrometer. The simple structure and small number of mirrors can help higher transmission efficiency be achieved and weak signals detection be implemented. The telescope is an off-axis parabolic mirror and the spectrometer is a modified Czerny-Turner spectral imaging system. Modified Czerny-Turner spectrometer contains a spherical mirror  a fixed plane grating and a toroidal mirror. By adjusting the incident angle to the collimating mirror and using toroidal mirror  coma and astigmatism were corrected well. We also optimize distances between the grating to the focusing mirror and the focusing mirror to the image plane to improve disadvantages of traditional Czerny-Turner structure. Designed results demonstrate that aberrations are substantially corrected  and high image quality can be obtained in broad waveband. The photon counting Wedge-Strip-Anode detector with micro-channel planes as the receiving plane is accepted for the instrument prototype. The other photon counting 2-D detector responding well for weak light such as Cross-Delay line detector and MAMA detector can also be used for detection. The calibration and performances testing system is made of a vacuum system  a deuterium lamp  a monochrometer and the instrument prototype. Results obtained from the experiment show that the spectral resolution is 2.4 nm and the spatial resolution is 80 m. The other calibration experiments are running. The technology of the spectrometer prototype is important for the research and applications of ionosphere remote sensing. 2011 SPIE.  
Simulation and experiment of the static FTIR based on micro multi-step mirrors (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2011: Sensor and Micromachined Optical Device Technologies, May 24, 2011 - May 26, 2011, Beijing, China
Liang J.; Liang Z.-Z.; Lv J.-G.; Fu J.-G.; Zheng Y.; Feng C.; Wang W.-B.; Zhu W.-B.; Yao J.-S.; Zhang J.
收藏  |  浏览/下载:25/0  |  提交时间:2013/03/25
In recent years  Fourier transform spectrometer (FTS) with small size and low mass is required in many applications with growing need for real-time and small platform spectral detection. In this paper  a micro Fourier transform infrared spectrometer (FTIR) based on spatial modulation mode was designed. This spectrometer has the advantages of high stability and simplified configuration. It also promises optical path differences (OPD) with high precision  as MOEMS technology is used in manufacturing the key components. The simulation and the experiments with regard to this FTIR configuration have been done. Firstly  the diffraction effect of the micro multi-step mirrors (MMSMs) is studied. We discuss the influence to the reversed spectrum by different mirror widths and different diffraction distances. Secondly  we simulate and analyze the influence of the source solid angle to the spectral resolution. Thirdly  we set up the theoretical model of the collimation error which is mainly from the defocus of the optical system and analyze the result caused by the collimation error. Fourthly  a new discrete Fourier transform arithmetic using least-squares cosines progression (LSCP) is proposed which can reconstruct the spectrum with nonuniform sampled signals. Finally  the MMSMs are fabricated used the MOEMS technology and the structural parameters are tested. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).  
Design and demonstration of micro multi-step mirrors and light source in micro FTIR (EI CONFERENCE) 会议论文
6th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, NEMS 2011, February 20, 2011 - February 23, 2011, Kaohsiung, Taiwan
Liang Z.; Fu J.; Feng C.; Liang J.
收藏  |  浏览/下载:28/0  |  提交时间:2013/03/25
To obtain high resolution  high signal-to-noise ratio (SNR)  high reliability and real time in wide spectral range  we study the space modulation Micro Fourier Transform Spectrometer (FTS) based on multi-step mirrors covering the spectral range of 3-5m and 8-12 m in theory and experiment. The influences of spectrum reconstruction caused by the diffraction and extended light source in Fourier Transform Infrared Spectrometer (FTIR) are analyzed. A method to reduce the noises in spectrum reconstruction and the relationship between coherent intensity and solid angle of light source are discussed. An extended light source with suitable size is chosen  considering the requirement of SNR and spectrum resolving power in the optical design. Furthermore  the fabrication of micro multi-step mirrors  which is the core part of FTS  is investigated. Three methods for fabricating multi-step micro mirrors are demonstrated. 2011 IEEE.  


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