Logo of the Physikalisch-Technische Bundesanstalt

Unit of Length

Working Group 4.31

Calibration and Testing of Laser Wavelength Standards

For dissemination of the unit of length, working lasers and secondary standards are linked up and calibrated with the laser wavelength standards of PTB via beat frequency measurements and wavelength comparisons. For this purpose, iodine-stabilized He-Ne lasers at 633 nm or frequency-doubled Nd:YAG lasers at 532 nm are used which comply with the recommendations of the International Committee for Weights and Measures (CIPM). When stabilization is performed by means of saturated absorption to the components d - j of the transition 11 - 5 R(127) of the
127I 2-molecule, the measurement uncertainties are - compared to a PTB reference laser - less than 12 kHz.

At regular intervals, the frequencies of the reference lasers are traced back by means of frequency measurements.

Iodine-stabilized HeNe laser for the calibration of laser wavelength standards


Dr. Uwe Sterr
Phone.: +49 531-592 4310
E-mail: Uwe Sterr

Klemens Budin
Phone: +49 531-592 4317
E-mail: Klemens Budin