Use of a double-pass Michelson interferometer for high-spectral-resolution lidar measurements of optically thick clouds.

A 355-nm high-spectral-resolution lidar (HSRL) method using a double-pass Michelson interferometer (MI) was developed for cloud measurements. Passing the received backscattered light through a single interferometer twice more effectively suppressed Mie scattering than single-pass systems. This study demonstrated that the effective transmittance for Mie scattering by the double-pass system was approximately one-fourth that of a single-pass system. The result was an approximately twofold reduction of the measurement errors for cloud extinction and backscatter coefficients. Because the double-pass MI has a simple configuration and allows for a wide field-of-view, it is a promising filter for ground-based HSRLs.