Field-widened Michelson interferometer for spectral discrimination in high-spectral-resolution lidar: practical...

Area of Science:

• Optics and Photonics
• Atmospheric Science
• Instrumentation

Background:

• High-spectral-resolution lidar (HSRL) requires precise spectroscopic discriminators for atmospheric aerosol detection.
• Field-widened Michelson interferometers (FWMI) are potential candidates for this role due to their unique optical properties.

Purpose of the Study:

• To introduce a developed prototype field-widened Michelson interferometer (FWMI).
• To propose an experimental approach for optimizing FWMI assembly and evaluating its performance.
• To demonstrate the FWMI's suitability as a spectroscopic discriminator for HSRL applications.

Main Methods:

• Detailed description of the FWMI prototype's structure, specifications, and design.
• Implementation of an experimental optimization process for FWMI assembly.
• Simultaneous evaluation of FWMI comprehensive characteristics, including optical path difference (OPD) variation and spectral discrimination ratio (SDR).

Main Results:

• Optimized FWMI achieved peak-to-valley (PV) and root-mean-square (RMS) OPD variations of 0.04λ and 0.008λ, respectively, within a 1.5-degree divergent angle range.
• An active locking technique enabled FWMI frequency locking to the laser transmitter with 27 MHz accuracy for over an hour.
• A practical spectral discrimination ratio (SDR) exceeding 86 was achieved for incident beam divergent angles below 0.5 degrees.

Conclusions:

• The developed FWMI demonstrates significant potential as a spectroscopic discriminator for ground-based HSRLs.
• The proposed design and optimization process for the FWMI are feasible and effective.
• This work provides a valuable foundation for future HSRL developments utilizing FWMI technology.