Study On The Key Technology Of Silicon-based Micro-Spectral Imaging System

Spectral imaging system can perform an analysis on the target based on both material and geometric information which is a new technique with the potential to promote the production efficiency and the life quality.However,due to the existence of the individual spectral components,there are lots of optical components to cope with the function of spectral components in the traditional spectral imaging system.As a result,the entire system is bulky,complex and with high cost,which has a negative effect on the application range of such technology.This paper focuses on the research and development on the micro spectral imaging system which will expand the application field of classical spectral imaging system.The main research contents in this thesis include:1.The design and manufacture flow optimization of monolithic micro spectral imaging system:(1)The parameter estimation of the micro spectral imaging system:The Bragg mirror is proposed to be applied for estimating the simulator parameter instead of the FP(Fabry Perot)interferometer,which will decrease the cost of opening a test window in the silicon wafer and therefore increase the efficiency of the design flow;(2)The road map and the prototype of micro spectral imaging system is proposed to fit the classical spectral imaging system including both line-scan and mosaic pattern.A monolithic micro spectral imaging system with two bands is fabricated with qualified performance in pixel size,sensor size and quantum efficiency.2.The design and manufacture of separated micro spectral imaging system:(1)Design and manufacture of mid infrared mosaic spectral imaging filter,design and develop mid infrared mosaic spectral imaging filter with 3 different spectral channels with high transmittance in the high pass zone and low transmittance in the rejection zone;(2)MEMS spectral filter,the design principle and technology of MEMS filter are analyzed,and the fabrication is realized in the visible spectrum,which lays the foundation for the expansion of spectrum range of MEMS filter.3.Integration and application of micro spectral imaging system:(1)Light and small UAV(Unmanned Aerial Vehicle)spectral imaging payload: Develop the basic form of light and miniaturized spectral imaging payload based on snapshot micro spectral imaging system.Data acquisition and cluster analysis of cyanobacteria bloom on water surface were carried out on UAV platform.The results show that the acquired spectral imaging data are consistent with the growth and distribution characteristics of cyanobacteria bloom,which offers the possibility and potential for lake and river quality surveillance based on a light spectral imaging load on UAV.(2)The portable spectral imaging equipment based on the micro spectral imaging system is developed,which has the data acquisition ability and basic data processing ability for spectral image data cube and can be used as a data acquisition equipment and prototype verification machine to support the application expansion in a variety of application scenarios.The main innovation in this thesis includes1.A fast and feasible method is proposed for FP simulator parameter estimation,the error of the simulator is less than 10%.: Performing FP simulator parameter estimation based on the experiment result of Bragg mirror leads to the reduction of the cost and time by avoiding opening a window on the back of silicon wafer to test the FP transmittance.After the estimation,the error of the simulator is less than 10%.2.A new way of increasing quantum efficiency is proposed by introducing a matching layer,the quantum efficiency is increased to 40%: The light coupling efficiency into the silicon-based detector is increased by introducing a well-designed optical matching layer.For the first time,a 5-megapixel single-chip dual band micro spectral imaging system is realized on a 1.1μm pixel sensor,and the quantum efficiency is increased to 40%,the similar technology can be applied in fabricating multi-spectral or even hyperspectral imaging system and.3.Thanks to the design and manufacturing method for a FP cavity with non-shared substrate layers,a pixel-wise mid infrared mosaic filter with a broad band and free spectrum range is fabricated with an optical efficiency higher than 85% in the transmitted band and lower than 5% in the rejection band.