Mode-locking of an atmospheric pressure cross-excited electrically pulsed CO₂laser

Self-mode-locking of a cross-excited electrically pulsed CO2laser has been observed and studied as a function of cavity length and operating pressure. The best results are obtained at a pressure of 450 torr with cavity lengths on the order of 1m. Two-ns duration pulses have been measured, the shortest pulses observed to date at 10.6-μ wavelength. With longer cavities more axial modes are locked, resulting in a longer dead time between pulses; however, the pulsewidths increase with increasing cavity length. Mode-locking was not improved by the use of the bleachable absorber SF6.