Research On Fourier Transform Hyperspectral Mueller Matrix Imaging Technology Based On FLC

Hyperspectral Mueller matrix imaging technology can realize the acquisition of spatial images,spectral images and Mueller matrix images simultaneously.This technology is able to accurately measure the frequency information and polarization information of the reflected or transmitted light from detection target,reflecting the material composition and surface structure characteristics of the target.It has important significance and application value in biomedicine,food safety,identification of criminal evidence and so on.This paper proposes a Fourier transform hyperspectral Mueller matrix imaging technology based on ferroelectric liquid crystal(FLC).It takes advantage of the high spectral resolution and high luminous flux with combining interference imaging spectrometer and Mueller matrix imaging technology.So,the Mueller matrix imaging detection of the target can get higher accurate and achieve Mueller matrix imaging at more spectral band,which improves the information richness of the target detection.The structure of the entire hyperspectral Mueller matrix imaging system is simple,compact and easy to adjust,it offers a new idea for the spectral Mueller matrix imaging technology.The interference imaging spectrometer using a birefringent shear plate and a birefringent compensation plate to bring in optical path difference and it can better suppress the non-linearity of the optical path difference and the non-uniformity of the longitudinal field resolution.Both the polarization state generator and polarization state analyzer use the structure of two wave plates and two FLCs,and the genetic algorithm is used to optimize the fast axis angle of the FLC and wave plate,which significantly reduces the system noise and error transmission.In this paper,first,the basic principles of hyperspectral Mueller matrix imaging are intorduced.Starting at the Fourier transform spectrum detection technology theory and the polarization modulation information is added to the spectral signal,so the formula for the spectral Mueller matrix is derived.The polarization modulation mechanism and spectral restoration theory also be discussed.Subsequently,the propagation laws of o-light and e-light in birefringent crystals are analyzed in detail.The wave normal analysis method is used to derive the optical path difference formula of a single birefringent plate.According to the system's requirements for spectral resolution and luminous flux,and suppressing zero optical path position deviation and quadratic term optical path difference,the thicknesses and clear apertures of shear plate and compensation plate in the birefringent interferometer are designed.The non-linear optical path differences,total optical path differences and interference fringes of the birefringent interferometer are analyzed.Next,the error theory of the target Mueller matrix measurement is studied.The concept of the condition number in the matrix analysis is used to derive the noise and error transfer function of the Mueller matrix measurement.Under the constraint of minimizing the matrix condition number,the genetic optimization algorithm is used to obtain the fast axis of the phase delay device when error function value approaching minimal,and the optimized and unoptimized results are simulated and compared by adding errors and noise,which verified the necessity of optimal design.Finally,a hyperspectral Mueller matrix imaging device was mounted in the laboratory,and the optical components of the device were accurately adjusted.The device was used to capture spectral polarization imaging data and restore the spectral images and Mueller matrix images,which obtained a good result.As a result,the restoration results are analyzed and discussed in combination with the characteristics of the target,which confirms the feasibility and effectiveness of the proposed method.