Absolute laser ranging by time-of-flight measurement of ultrashort light pulses [Invited]

Abstract

Ultrashort pulse lasers are emerging as an advanced tool of distance measurement, with their unique temporal and spectral characteristics being extended to diverse principles of absolute ranging and instrumentation. Here, a systematic methodology is presented for absolute ranging by means of the time-of-flight measurement of ultra-short light pulses using dual-comb asynchronous optical sampling. Based on an elaborate uncertainty analysis, influencing system parameters such as the pulse duration, repetition rate, and averaging time are optimized to achieve a sub-mu m measurement accuracy. The absolute ranging system developed in this study demonstrates a combined standard uncertainty of 0.986 mu m for a 0.5 ms averaging over a distance range of 3.0 m, with a further reduction to 0.056 mu m when the averaging time is increased to 0.5 s. The outstanding performance leads to unprecedented multitarget applications: machine feed control with thermal error compensation in real time as well as the nondestructive inspection of multilens assembly in a production line.