Wavelength references for interferometry in air.
Cavity-mode wavelengths in air are determined by measuring a laser's frequency while it is locked to the mode in vacuum during a calibration step and subsequently correcting the mode wavelength for atmospheric pressure compression, temperature difference, and material aging. Using a Zerodur ring cavity, we demonstrate a repeatability of +/- 2 x 10(-8) (3sigma), with the wavelength accuracy limited to +/- 4 x 10(-8) by knowledge of the absolute helium gas temperature during the pressure calibration. Mirror cleaning perturbed the mode frequency by less than deltav/v approximately 3 x 10(-9), limited by temperature correction residuals.
Fox
Richard W
RW
National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA. richard.fox@nist.gov
Washburn
Brian R
BR
Newbury
Nathan R
NR
Hollberg
Leo
L