Simulation And Optimization Design Of Micro Fourier Transform Infrared Spectrometer

Fourier transform infrared spectrometer has the advantages of multi-channel,highflux,accurate wave number and low stray light.It is widely used in environmental monitoring,medical analysis,space exploration,military reconnaissance,antiterrorism and anti-terrorism and meteorological detection.A miniature FTIR spectrometer with a multi-step ladder micro-mirror interferometer replaces the moving mirror structure of a time-modulated FTIR spectrometer with two orthogonally placed multi-step ladder micro-mirrors,and replaces the traditional one with a light-grating beam splitter The parallel plate beam splitter simplifies the multilens rear optical system with a microlens array,eliminates distortion,simplifies the instrument structure,and reduces the size and weight of the instrument.Therefore,the system has the advantages of stable performance,compact structure and good repeatability.In this paper,the research work of the ?FTIR spectrometer system is mainly carried out,and the main results are as follows:(1)The design and research of the light grid beam splitter was carried out.As a key component of the ?FTIR interferometric system,the structural accuracy of the light grating beam splitter and the consistency of the depth of the beam window are the important factors determining the noise and sampling interval.According to the requirements of the system,a light grating beam splitter with different structures of 10 cycles and 20 cycles was proposed.The structural parameters were designed.The error of the light grating beam splitter was analyzed by modeling and simulating the ?FTIR spectrometer system.The light grating beam splitter was fabricated by wet etching process,and the corrosion depth error test was carried out.The error analysis of the test results was carried out.(2)The fabrication and testing of the microlens array was completed.Through the modeling and simulation,the optical properties of the microlens array and the influence of the overall shape of the silicon wafer on the spectral recovery are analyzed.The surface roughness of the fabricated microlens array and the uniformity of the single lens height in the microlens array were tested,and the vector height consistency error was calculated and analyzed.(3)The construction of the test platform and the adjustment of the optical components were completed.The infrared light source was measured by spectroscopy,and the interferogram was obtained on the infrared cooling detector.The recovery spectrum of the light source was obtained by sampling and correcting the interferogram and discrete Fourier transform.