Research On Multi-Mode Coupled Imaging Detection Method Based On Liquid-Crystal Micro-Nano-Beam-Manipulating And Key Technology

The multi-mode coupled imaging detection technique based on micro-nano-lightbeammanipulating is a new imaging approach.By synergistically introducing imaging lightwave elements including wave-vector and polarization and spectrum and wavefront into imaging detection chain,it can fundamentally vary the single energy transfer and information interpretation manner of the traditional imaging methods with object-image conjugation as the core.Therefore,the information acquisition capability as well as the target and environment adaptability can be significantly enhanced.Liquid crystal(LC)materials generally exhibit significant anisotropy in an ultra-broad wavelength range,and can perform functional adjustment of incident lightbeams according to the wave-vector or polarization or spectrum or amplitude with an applied electric-field.This feature is the physical basis for realizing the multi-mode coupled and micro-nano-lightbeam-manipulating imaging detection(MCMID).In this dissertation,the basic methods and key technologies for realizing the MCMID are developed based on the adjusted electro-optical properties of the functioned LC materials,so as to provide foundermental techniques with obviously intelligent characters.The main work and innovations are as follows:Aiming at the limited depth-of-field of conventional LC-based imaging detection,a compound-eye imaging method based on microaperture array nested liquid crystal microlens array(MAN-LCMLA)is proposed.The multi-focus adjusting characteristic of the MAN-LCMLA is analyzed,and a compound eye imaging system based on the main MAN-LCMLA is constructed for significantly extending the depth-of-field of the compound-eye light-field imaging.Based on the lightbeam amplitude measurement,the wave-vector information can be obtained and interpreted in a relatively wider spatial region,and thereby effectively extending the applications of the LC-based multi-mode coupled imaging technology.To solve the problem that the conventional LC-based light-field imaging is difficult to quantitatively evaluate the polarized degree of imaging lightbeams and the spatial resolution loss of LC-based polarization imaging,a polarized light-field coupled imaging technology based on electrically tunable LC device is proposed.By collecting the raw light-field images with different polarization angle including 0° and 60° and 120°,an all-in-focus rendering based on parallax detection is performed.The all-in-focus rendering images and all-in-focus linear polarization images are efficiently obtained corresponding to the polarization angles mentioned.In the case without any macroscopic displacement,both the polarization imaging and the light-field coupled imaging and further the key information interpretation can be conducted effectively.Thus the multi-mode lightwave information such as the amplitude and the polarization and the light-field can be acquired.In order to establish a relevance between the electrically addressed focal length of the LC multi-mode coupled imaging architecture and the image processing algorithms,and then solve the problems of information acquisition dimension being low and still requiring image registration during focal stack imaging,a LC-based electrically addressed focal stack lightfield imaging method with extended depth-of-field,is presented.An electrically addressable3 D focal stack is constructed under the condition of no macroscopic displacement,and then the all-in-focus rendered images with a relatively large depth-of-field obtained through utilizing Laplacian operator.At the same time of avoiding image registration,the information collection dimension of the focal stack imaging is increased,and the imaging application extended,and thus a solid foundation for practical application constructed.For the construction requirement of LC-based polarization vortex light-field for performing multi-mode coupled imaging detection,a vector lightbeam manipulation and device-oriented technology based on LC lightbeam converging controlled electrically,is suggested.By the light-induced alignment and the polymer ribbon alignment of functioned LC materials,the LC-based lightbeam converging devices are fabricated.The orthogonal separation of the featured vector lightbeams,the generation of broad-spectral vector lightbeams and the adaptive lightbeam converging or even focusing are realized.Both the method and the key technologies for supporting practical applications of electrically controlled LC-based complex light-field manipulation and guiding the continuous development of the multi-mode coupled imaging detection technology based on special structured light-field,are provided.According to the demand of extending spectral domain for LC microcavity interference filtering imaging,a basic method and the device-oriented technology based on the electrically controlled LC Fabry-Pérot(LC-FP)microcavity interference filter in a wide wavelength range covering the ultraviolet and the visible and the infrared domains,is proposed.The deviced LC-FP is achieved using a kind of nematic LC mixture for achieving the typical electrically selecting and adjusting and jumping of spectral lightbeam outfrom the LC-FP.Several electrically tunable sharp transmission peaks can be observed in the ultraviolet domain of 250～350 nm and the typical full width at half maximum being less than 0.04 nm.In the visible domain of 600～780 nm,an electrically tunable spectral resolution of 5 nm being achieved.In the infrared domain of 2000～2250 nm,an electrically tunable spectral resolution of better than 3.5 nm being reached.Both the methods and the key LC devices for developing ultra-broad-domain LC-based multi-mode coupled imaging detection technology,are provided by the schemes developed in this dissertation.