ABSOLUTE FREQUENCY MEASUREMENT OF THE 118.6-μm WATER-VAPOR LASER TRANSITION

Abstract
The frequency of the 118.6‐μm water‐vapor laser transition has been measured as 2,527,952.8 MHz in a harmonic mixing experiment. Accuracy of several parts in 108 has been obtained by phase locking the klystron harmonic source to a tunable crystal oscillator and by centering the laser to the Lamb dip.