Variation of the duration of pulses emitted by a mode-locked carbon dioxide laser

It was demonstrated experimentally that the duration of CO₂ laser pulses with a predominantly homogeneous gain profile could be controlled at pressures of 6–100 mm Hg. The duration was varied within the 25–500 nsec range by the spontaneous locking of the transverse modes. The number of these modes and the mode spacing could be altered either using the caustic of the resonator or a wedge-shaped NaCl plate.