Q-switching is a laser technique used to produce short, high-intensity pulses by temporarily storing energy in the gain medium and then releasing it all at once.
How It Works:
- The “Q” refers to the quality factor of the optical cavity, which affects how well it stores light.
- Initially, the cavity’s Q is kept low, preventing laser action while the gain medium is pumped to build up energy.
- At the right moment, the cavity Q is rapidly increased, allowing the stored energy to be released as a brief, powerful pulse.
Types of Q-Switching:
- Passive Q-switching: Uses saturable absorbers that become transparent at high light intensities.
- Active Q-switching: Uses external devices like acousto-optic or electro-optic modulators to control cavity Q.
Q-switching enables nanosecond-scale pulses with peak powers much higher than continuous-wave lasers, and is widely used in material processing, laser ranging, and medical applications.