Beat frequencies between the transverse modes of an unstabilized cw CO2 laser were studied by detecting the homodyne signals emitted by the laser. Frequency pulling was observed and a resulting mode spacing reduction of up to 8% was measured. The dependence of mode pulling on total gas pressure was measured and was found to be in fair agreement with theory. The observed effect is important in some laser tuning techniques where it leads to a reduction of the tuning range and a nonlinear dependence of the laser frequency on cavity length.
© 1984 Optical Society of America
Original Manuscript: September 3, 1983
Published: March 1, 1984
Uri P. Oppenheim and Mira Naftaly, "Observation of mode pulling in a CO2 laser," Appl. Opt. 23, 661-664 (1984)