Frequency-switchable CO2 laser: design and performance

A CO(2) laser with an intracavity CdTe modulator is described whose output frequency can be rapidly switched or chirped, while the output intensity remains constant to better than 2%. Currently, frequency switches of up to 20 MHz in 50 nsec can be performed, with the limitation being only the performance of the pulse generator which drives the crystal. The problems which must be addressed in designing such a laser are discussed along with the approaches we have taken to solve them. The laser performance is analyzed and compared with theory, and a novel laser frequency locking scheme is presented which eliminates switching transients in the CO(2) gain medium.