Comparisons between field-widen Michelson interferometer and Fabry-Perot interferometer as the spectroscopic filter in high spectral resolution lidar

Abstract

One of the pivotal challenges in high spectral resolution lidars (HSRLs) is the spectral discrimination process, which brings about more straightforward and accurate retrieval without a priori assumptions in contrast to standard backscatter lidars. Inteferometric filters such as Fabry-Perot interferometer (FPI) has shown great convenience for spectrally separating the Rayleigh and Mie scattered elements in HSRL returned signals. Based on interference of two incident beams, the field -widen Michelson interferometer (FWMI) may be also the same potential in this application as FPI in spite of some performance differences. In this paper, we concentrate on the performance comparisons of FWMI with FPI as spectroscopic filter in HSRL from the inspections of spectral discrimination characteristic, field of view (FOV) tolerance, the efficiency of power collection, etc. All these analytical comparisons are quantificational and will be beneficial to reasonable choice among the two optical filters for HSRL. The results indicate that in spite of a litter lower transmittance when processing the radiation with very small divergence and more rigorous tolerance for temperature stability and surface flatness compared with FPI, FWMI is still very competent in this spectral filtering process for its remarkable spectral discrimination characteristic and efficient photons collective ability which attributes to its field widen design and intrinsically outstanding spectral separation performance.