Frequency stabilized, passively Q-switched, CO2laser

A novel method of simultaneously stabilizing the oscillating frequency and pulse repetition frequency (PRF) of a passively Q-switched CO2laser is presented. The method is based upon the direct sensing of the PRF which is a function of the laser´s operating point on the frequency dependent CO2gain and SF6absorption profiles. The tunable, passively stable laser uses tandem sealed-off CO2gain and SF6absorption cells inside of a dispersive cavity. An error signal derived from the direct measurement of the PRF was used to actively stabilize the laser and maintain long-term operation for pre-selected conditions. Typically, frequency stable operation is obtained at stabilized PRF´s from 20KHz to 80 KHz with varying duty factors.