Broadband precision wavelength meter based on a stepping Fabry–Pérot interferometer

We have constructed a broadband apparatus for wavelength metrology capable of absolute accuracy at a level of better than 2 parts in 10 9 . An evacuated plane-parallel Fabry–Pérot interferometer with continuously adjustable mirror separation is used to compare the wavelength of a single-frequency tunable laser with that of an iodine-stabilized HeNe laser used as a wavelength standard. This work details apparatus construction, a thorough investigation of systematic errors, and data analysis. The wavelengths of five Doppler-free 130 Te 2 transitions in the region from 475.6 to 490.8 nm have been measured and are found to be in excellent agreement with previous measurements. In addition, the wavelengths of five previously unmeasured 130 Te 2 transitions spanning the region from 424.9 to 462.3 nm have been determined for use as new reference wavelength standards.