Stark effects in optically pumped CH(3)OH far infrared laser.

The Stark tuning properties of the 118.8-microm CH(3)OH FIR laser line pumped by the P(36) 9.4-microm CO(2) laser line are investigated. A laser model using a rate equation approach is derived. Observed Stark tuning effects include (1) frequency shifting of CH(3)OH absorption line, (2) frequency shifting of the FIR laser line, and (3) amplitude modulation of the FIR laser output. Frequency shifting of the CH(3)OH absorption line closer to the CO(2) pump laser line center results in a Stark enhancement of the 118.8-microm FIR laser line by a factor of 3 with a Stark field of 180 V/cm. Frequency shifting of about 7 MHz of the 118.8-microm FIR laser line is observed with a Stark field of 362 V/cm. Amplitude modulation characteristics of the FIR laser output are observed to be similar to those for Stark absorption modulation.