Free-Space Phase-Compensated Laser Gas Sensor

Stable detection under turbulence

Employs a half-mirror and mixer to extract and correct phase in free space, effectively suppressing phase fluctuations caused by atmospheric turbulence for long-range gas detection.

Tang, Qixing · Liu, Lu · Zhang, Yujun · Rao, Yuan · Liao, Juan · Wang, Yuwei · Gao, Yanwei

IEEE Transactions on Instrumentation and Measurement 2025

Advantages

Low limit of detection for 5 ppm NH3 is 8 ppb (1σ)

Fluctuation power spectral density suppressed below 20 Hz offset frequency

Phase compensation achieved with half-mirror and mixer