Slab RF-discharge carbon dioxide laser with active mode-locking

•Compact nanosecond CO2 laser.•Active mode-locking of long-wave mid-IR laser.•Experimental study of slab RF-discharge CO2 laser with mode-locking.•Numerical estimation of scalability for compact mode-locked CO2 laser. Mode-locking with an acousto-optic modulator was for the first time demonstrated for a repetitively pulsed (150 Hz) slab RF discharge CO2 laser. The mode-locked CO2 laser emitted trains of 5.5 ns pulses following with 27.25 MHz repetition rate. Mode-locking also affected the laser pulses envelope in respect to free-runing mode. The numerical estimation of the laser system scalability indicated an opportunity to develop a very compact CO2 laser emitting sub-nanosecond pulses.