Fourier transform wavemeter

Abstract

We describe a scanning Michelson interferometer and utilization of fast Fourier transformation in laser wavelength determination. The Fourier transformation method is demonstrated to be particularly powerful in cw multimode (diode) laser investigations and in cw single-mode laser long-term frequency stability measurements. An uncertainty less than 10−7 can be concluded from comparisons of a two-mode polarization stabilized 543-nm He–Ne laser with an iodine stabilized 633-nm He–Ne laser.