<title>Tunable laser sources for absolute optical interferometry</title>

Abstract

Absolute interferometry is based on the use of an optical synthetic wavelength generated by two beating lasers. To obtain high-resolution, absolute measurements over a wide range it is necessary to use multiple synthetic wavelengths. A tunable synthetic wavelength generator would be the ideal solution for this purpose. In this paper, two configurations based on the use of two diode lasers and two diode-pumped Nd:YAG lasers are discussed. The paper presents the optical set-up for the generation of the synthetic wavelength, the necessary frequency-locking electronics, and experimental results from two prototypes.