Laser wavelength measurements

Abstract

A review is made of developments in wavelength measurement practice over the last 5 years. The rapid development of single‐frequency tunable dye lasers has led to a requirement for quick and easy wavelength measurement at accuracies of 1 part in 106 or better. This has stimulated the development of moving‐carriage interferometers and of methods of image sensing with detector arrays or vidicon tubes. There has also been progress in the attainment of very high accuracy in wavelength comparisons of stabilized lasers, now nearly matching the laser reproducibilities of a few parts in 1011. The limitations to accuracy seem to be predominantly the defects of optical surfaces and uncertainties arising from diffraction effects.

Infrared and optical frequency standards

“…In the near future when it will become possible to measure frequencies in the optical band and to lock lasers and masers to each other [Jimenez, 1979], lasers can become the oscillators on the basis of which an atomic time unit may be created. As for measurement of wavelengths, their comparison may be performed with an accuracy up to 10 -lø [Rowley, 1979]. The production of the etalon which serves as a standard of time and length simultaneously is the overriding problem at present.…”