Rapid and precise distance measurement using balanced cross-correlation of a single frequency-modulated electro-optic comb

TL;DR

This paper introduces a fast, high-precision optical ranging method using a modulated femtosecond electro-optic comb and balanced cross-correlation, achieving nanometer accuracy at megahertz refresh rates with an unlimited ambiguity range.

Contribution

The authors develop a novel time-of-flight measurement technique combining frequency-modulated electro-optic combs and balanced detection for rapid, precise, and large-range distance measurements.

Findings

Distance measurement within 500 ns

Ultimate ranging precision of 5 nm

Real-time displacement tracking at 172 MHz refresh rate

Abstract

Ultra-rapid, high-precision distance metrology is critical for both advanced scientific research and practical applications. However, current light detection and ranging technologies struggle to simultaneously achieve high measurement speed, accuracy, and a large non-ambiguity range. Here, we present a time-of-flight optical ranging technique based on a repetition-frequency-modulated femtosecond electro-optic comb and balanced nonlinear cross-correlation detection. In this approach, a target distance is determined as an integer multiple of the comb repetition period. By rapidly sweeping the comb repetition frequency, we achieve absolute distance measurements within 500 ns and real-time displacement tracking at single-pulse resolution (corresponding to a refresh rate of 172 MHz). Furthermore, our system attains an ultimate ranging precision of 5 nm (with 0.3 s integration time). Our method uniquely integrates nanometer-scale precision, megahertz-level refresh rates, and a theoretically unlimited ambiguity range within a single platform, while also supporting multi-target detection. These advances pave the way for high-speed, high-precision ranging systems in emerging applications such as structural health monitoring, industrial manufacturing, and satellite formation flying.