Active and passive Q-switching

Active and passive Q-switching are techniques used to produce short, intense laser pulses. Active Q-switching involves using an external device, such as an acousto-optic or electro-optic modulator, that rapidly switches the laser's internal light gain, releasing stored energy as a pulse at controlled times. Passive Q-switching uses a special material called a saturable absorber inside the laser cavity that automatically blocks or absorbs light until enough energy accumulates, then suddenly becomes transparent, emitting a pulse. Both methods create powerful, short laser bursts, but active switching allows precise control, while passive relies on the material’s properties for timing.