Theory,Design And Experiment Of Snapshot Infrared Fourier Transform Imaging Spectrometer

Fourier transform spectrometer(FTS)is widely used in many application scenarios,especially in the infrared band,because of its advantages of multi-channel and high throughput.Fourier transform imaging spectrometer(FTIS)combines Fourier transform spectroscopy and imaging technology,which can acquire three-dimensional information(two-dimensional spatial information and one-dimensional spectral information)of targets,and is widely used in environmental monitoring, resource exploration,military target identification and biomedical diagnosis.At present,most FTS and FTIS have scanning structure,which limits the volume,weight,real-time performance and stability.In order to realize the light miniaturization of spectral and imaging spectrometer,we first studied a Fourier transform infrared spectrometer based on micro-mirror and micro-lens array of Micro-Optic Electric-Mechanical System(MOEMS).On this basis,the theory,design and experimental research of snapshot infrared Fourier transform imaging spectrometer(SIFTIS)are carried out.The research contents and innovative achievements of this paper mainly include the following four parts:(1)The theoretical design and experimental research of MOEFTS were carried out:we establish the field-of-view integral model of interference image intensity of the MOEFTS.The influence of light source field of view on spectrum is analyzed while introducing micro-lens array,and the light source field of view is determined.The optical design and achromatic optimization for the MOEFTS are completed through using micro-optical elements.The physical light transmission process of the system is simulated,and the processing flow of reconstructed spectral data of an interference image point array is established.We numerically calculate the translation and rotation position errors of the key device micro-lens array,and establish the error transfer model to determine the error tolerance.The MOEFTS experimental system is built,and perform the spectral wavenumber calibration experiment and the sample substances spectrum measurement tests,the measured peak wave drift is less than 4cm^-1.The results verify the qualitative identification ability of the MOEFTS.We complete the assembly and adjustment of the MOEFTS lightweight prototype.(2)Based on the research results of MOEFTS,the theory and key devices of SIFTIS were studied:we design the structural optical parameters of the interference core components stepped micromirrors according to the SIFTIS index.Based on the Monte Carlo method,we establish the transfer model between the wedge block inclination error(step height error),substrate processing error,and the spectral error when the stepped micromirror is manufactured via the substrate stacking.And the manufacturing errors tolerance of the stepped micromirrors are determined.We establish the stepped micromirrors manufacture system to complete the fabrication for the stepped micromirrors.We establish the optical transmission model of the SIFTIS to analyze the spectral error caused by the wave aberration of the collimating system and the lens array.The SR algorithm is proposed to correct the spectral error caused by the wave aberration of the system.The spectral error caused by the tilt error of lens unit of lens array is analyzed,and the SR and the IMR algorithm is proposed to correct the spectral error caused by the tilt error of lens array.(3)The research on the optical system design of SIFTIS was carried out:we utilize the global matching after the independent design method to design and optimize the SIFTIS.Considering the requirement of high focal depth when the stepped micromirrors are used as the image planes and the requirement of eliminating distortion in multi-channel snapshot imaging,we use the refractive diffraction lens and telecentric optical structure to design the relay system RS.According to the matching relationship with RS,the optical design optimization of multi-channel system MS is completed.Based on two different applications for SIFTIS,the near field imaging system NIS for the near field targets detection and the remote sensing imaging system RSIS for the remote sensing application,the MTF at the cut-off frequency of the optimized optical system is better than 0.5.We obtain the simulated interference image array and reconstructed spectrum through the physical light transmission process simulation.(4)The experimental research on the spectrogram measurement of SIFTIS was carried out:we complete the manufacturing and packaging of the SIFTIS systems and components,and build a near field targets experimental system in the laboratory environment.The preliminary adjustment of the SIFTIS optical path is completed,and the interference fringe array is obtained.It is proved by physical optical simulation that the spectral peak drift caused by the device adjustment error of the stepped micromirrors can be corrected via spectral wavenumber calibration.The spectral wavenumber calibration experiment and the target imaging spectrum measurement experiment for SIFTIS are designed and completed.The results verify the image resolution and spectral recognition ability of the SIFTIS.The imaging spectrum measurement experiment of the combustion flame of the alcohol lamp is designed and performed,and the absorption spectral characteristic peak of CO₂ generated by the combustion of the alcohol lamp is successfully identified,the measured peak wave drift is less than 0.7 cm^-1,which verify the imaging spectrum measurement ability of the SIFTIS for dynamic targets.