Improved performance of semiconductor laser tracking frequency gauge

TL;DR

This paper reports significant improvements in the accuracy of a semiconductor-laser tracking frequency gauge, enhancing its potential for precise distance measurements in gravity research and space astronomy.

Contribution

The authors present a doubled incremental distance accuracy and a twentyfold improvement in absolute distance accuracy for the tracking frequency gauge.

Findings

Incremental distance accuracy improved to 0.9 pm in 80 s.

Absolute distance accuracy improved to 0.17 μm in 1000 s.

Restoration of distance measurement accuracy after interruption using combined methods.

Abstract

We describe new results from the semiconductor-laser tracking frequency gauge, an instrument that can perform sub-picometer distance measurements and has applications in gravity research and in space-based astronomical instruments proposed for the study of light from extrasolar planets. Compared with previous results, we have improved incremental distance accuracy by a factor of two, to 0.9 pm in 80 s averaging time, and absolute distance accuracy by a factor of 20, to 0.17 $\mu$m in 1000 s. After an interruption of operation of a tracking frequency gauge used to control a distance, it is now possible, using a nonresonant measurement interferometer, to restore the distance to picometer accuracy by combining absolute and incremental distance measurements.