Design And Integration Of Infrared Spectrometer System Based On Microstructure Optics

Infrared spectrometer can be used for analysis of various substance components qualitatively or quantitatively.As an advanced scientific instrument based on interference spectrum measurement technology,Fourier transform infrared spectrometer has many advantages,such as high luminous flux,large channel number,accurate measurement,good repeatability and so on.It has been widely used in many fields,such as detection of polluted gas,poisonous substances,component and content of food and drugs,medical diagnosis and process control of industrial production.On this basis,the Fourier transform infrared imaging spectrometer,as a typical representative of imaging spectrum technology,can obtain the two-dimensional spatial information and one-dimensional spectral information of the measured target simultaneously.It has more comprehensive functions than the infrared spectrometer,and its application field has been expanded.In recent years,production safety situation has become increasingly severe.Environmental emergencies are in a high incidence period,and environmental safety is facing severe challenges.In particular,the sudden disaster and accidents caused by the frequent leakage of toxic and harmful chemicals not only have a large area and many leakage points,but also the composition of polluting chemicals is mixed and unknown.There is an urgent need for a miniature on-site detecting instruments with large field that can be used in various complex environments stably and reliably.In view of the above application requirements,we propose a static infrared spectrometer based on microstructure optics,which makes the system achieve good stability and effectively reduce the volume and weight.Based on this research,we propose an infrared imaging spectrometer with microstructure optical devices as the core,which can not only obtain the spectral data of the target,but also obtain optical imaging of the target,which can be applied to the large field of view monitoring of sudden disasters and pollution sites.The research work of this thesis mainly includes the following three parts:1.The design idea of infrared spectrometer based on microstructure optics is proposed.Microstructure optical devices such as silicon-based refractive diffraction lens,multistage micro mirror made by MOEMS technology and silicon-based micro lens array are used to replace the moving mechanism of traditional interference spectrometer and traditional infrared optical lens,so as to realize the miniaturization and high stability of the instrument.The design and image quality evaluation of the optical system and core microstructure optical devices of the spectrometer are carried out,and the experiment platform is built to verify the principle of the instrument.On this basis,the overall design,component manufacturing,integrated assembling and optical parameter test of infrared spectroscopy instrument are studied.The spectral resolution of the infrared spectrometer based on microstructure optics is 7.9cm^-1.2.The design idea and fabrication method of infrared dual band dual channel imaging spectrometer and static interference core device based on microstructure optics are proposed.The system design of medium wave infrared single channel imaging spectrometer and medium/long wave infrared dual channel imaging spectrometer as well as the design,manufacture and detection method of microstructure optics device are studied.The data processing method and high-precision image registration method of infrared spectrometer are studied.Through the modular design,the scheme of folding optical path,the switching design of the symmetrical lifting mirror group of the interference channel,the entire focusing design of the front imaging system,and the design of double shafting truss in the instrument,the optical characteristics of the instrument and the compactness and stability of the light and structure are realized.The simulation results show that the transfer function of the instrument optical system at the Nyquist frequency of 17lp/mm is greater than 0.6,and the imaging quality is good.3.A computer-aided assembling method and performance index testing method for medium/long wave infrared dual channel imaging spectrometer based on microstructure optics are proposed,and the influence of switching mirror positioning repeatability on the system is studied.The high-precision integration of the interference system is realized by using the assembling method of three-point fine polishing.The results of performance test and field test show that the two channel spectral resolutions of medium/long wave infrared dual channel imaging spectrometer are 60.5cm^-1 and 3.9cm^-1 respectively,the modulation transfer functions of medium wave and long wave at Nyquist frequency are 0.3808 and 0.307,and the noise equivalent temperature difference is 0.1080K and 0.1851K,which realizes the system design index.