Stabilization of 48- and 57-&#x00B5;m CH<inf>3</inf>OD lasers pumped by 9R(8) CO<inf>2</inf> laser for two color interferometer

Abstract

A two color far-infrared (FIR) laser interferometer of beat modulation type using 48-and 57-μm CH 3 OD lasers pumped by 9R(8) CO 2 laser has been developing for plasma diagnostics. The pump 9R(8) CO 2 laser frequency, 48-and 57-m CH 3 OD laser outputs and FIR beat frequency have been stabilized preliminary. The power stability of pump CO 2 laser of < ± 0.6 % and the frequency stability of < ± 0.78 MHz at the line center for 40 min. have been obtained by using external Stark cell modulation. For the twin type FIR laser system, an output stability of ± 2.4 % and an beat signal frequency of 765 ± 27 kHz for 40 min. have been obtained by controlling the cavity length for the 57-μm CH 3 OD laser.