Portable Pulsed Coherent Lidar for Noncooperation Targets at the Few-Photon Level

Area of Science:

• Optics and Photonics
• Remote Sensing
• Laser Technology

Background:

• Coherent lidar systems suffer from decoherence, especially over long distances.
• Maintaining a small laser spot is crucial for suppressing echo light decoherence from noncooperative targets but is challenging.
• High sensitivity lidar is needed for effective long-distance measurements.

Purpose of the Study:

• To demonstrate a pulsed coherent lidar with high sensitivity at the few-photon level.
• To reduce the decoherence effect in long-distance coherent lidar measurements.
• To enable long-distance laser ranging and imaging for noncooperative targets.

Main Methods:

• Utilized a phase plate to modulate laser wavefront for 100 m focusing.
• Employed coherent detection and time-of-flight (TOF) measurements.
• Implemented signal classification and superposition to extract weak echo signals from noise.

Main Results:

• Achieved long-distance laser ranging up to 105.0 m with a measurement uncertainty of 1.48 cm at 10 k/s.
• Successfully performed laser imaging at approximately 50.0 m.
• Demonstrated effective decoherence reduction using wavefront modulation.

Conclusions:

• The developed pulsed coherent lidar system offers high sensitivity and long-distance capabilities.
• The system is simple, portable, and eye-safe, suitable for practical applications.
• Potential applications include automated vehicle lidar systems.