Field-widened Michelson interferometer with an ultra-wide band and ultra-large field for spectral discrimination in high-spectral-resolution lidar

A novel field-widened Michelson interferometer (FWMI) with an ultra-wide band and ultra-large field is proposed to act as a spectral discriminator in shipborne oceanic high-spectral-resolution lidar (HSRL). By matching the primary spherical and chromatic aberration, a half field of view (FOV) over 10° throughout a spectral band from visible to near infrared (VIS-NIR) is achieved, which is about three times that of the classic single-wavelength FWMI and 50 times that of the widely used Fabry-Perot interferometer. Fabrication and assembly tolerances are analyzed, demonstrating that the tilt tolerance can be improved by four times as well combined with a pre-focusing system. Prototype experiments prove that the characteristics of an ultra-wide band and ultra-large field are technically achievable. The proposed method and results are expected to promote the development and widespread use of multi-wavelength oceanic HSRL.