Rapid and Precise Distance Measurement Using Balanced Cross‐Correlation of a Single Frequency‐Modulated Electro‐Optic Comb

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, a time‐of‐flight optical ranging technique based on a repetition‐frequency‐modulated femtosecond electro‐optic comb and balanced nonlinear cross‐correlation detection is presented. In this approach, a target distance is determined as an integer multiple of the comb repetition period. By rapidly sweeping the comb repetition frequency, absolute distance measurements within 500 ns and real‐time displacement tracking at single‐pulse resolution (corresponding to a refresh rate of 172 MHz) are achieved. Furthermore, the system attains an ultimate ranging precision of 5 nm (with 0.3 s integration time). This 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.