Two-Photon Dual-Comb LiDAR

TL;DR

This paper introduces a novel two-photon dual-comb LiDAR technique that achieves high sampling rates and sub-100 nm precision without requiring femtosecond lasers or complex data acquisition systems, enabling real-time, continuous distance measurements.

Contribution

The authors demonstrate a new dual-comb LiDAR method using two-photon detection and simple timing electronics, surpassing traditional sampling rate limits and simplifying data processing.

Findings

Achieved sampling rates up to 12 times the conventional limit.

Recorded sub-100 nm distance precision in real-time.

Enabled continuous, dynamic LiDAR measurements without complex hardware.

Abstract

The interferometric signals produced in conventional dual-comb laser ranging require femtosecond lasers with long-term f_CEO stability, and are limited to an upper sampling rate by radio-frequency aliasing considerations. By using cross-polarized dual combs and two-photon detection we demonstrate carrier-phase-insensitive cross-correlations at sampling rates of up to 12x the conventional dual-comb aliasing limit, recording these in a digitizer-based acquisition system to implement ranging with sub-100-nm precision. We then extend this concept to show how the high data burden of conventional dual-comb acquisition can be eliminated by using a simple microcontroller as a ns-precision stopwatch to record the time intervals separating the two-photon cross-correlation pulses, providing real-time and continuous LiDAR-like distance metrology capable of sub-100 nm precision and dynamic acquisition for unlimited periods.