Long-haul self-mixing interference and remote sensing of a distant moving target with a thin-slice solid-state laser

Area of Science:

• Laser Physics
• Optical Engineering
• Metrology

Background:

• Self-mixing interference in lasers is a known phenomenon.
• Long-haul applications are limited by factors like linewidth and feedback.
• LiNdP₄O₁₂ (LNP) lasers offer potential advantages due to their spectral properties.

Purpose of the Study:

• To investigate the feasibility of long-haul self-mixing interference using a thin-slice LNP laser.
• To evaluate the performance of LNP lasers in Doppler velocimetry and vibrometry over extended distances.
• To demonstrate the impact of narrow spectral linewidth on self-mixing applications.

Main Methods:

• Utilized a thin-slice LiNdP₄O₁₂ (LNP) laser.
• Employed heterodyne measurements to determine the laser's spectral linewidth.
• Performed self-mixing laser Doppler velocimetry and vibrometry with targets at a 2.5 km distance via single-mode fiber.
• Analyzed Doppler-shifted optical feedback.

Main Results:

• Observed effective long-haul self-mixing interference.
• Measured a narrow spectral linewidth of 16 kHz for the LNP laser.
• Successfully achieved laser Doppler velocimetry and vibrometry for targets 2.5 km away.
• Demonstrated the capability of the LNP laser to overcome long-distance limitations in self-mixing.

Conclusions:

• Thin-slice LNP lasers are suitable for effective long-haul self-mixing applications.
• The narrow linewidth of LNP lasers is crucial for high-precision remote measurements.
• Self-mixing velocimetry and vibrometry are feasible over 2.5 km using LNP lasers and optical fiber.