The Acousto-Optic Q-Switch (AOQS) is a technology that utilizes the interaction between sound and light to control the optical cavity loss. Acousto-optical Q-switching is to form ultrasonic waves through electro-acoustic conversion to make the refractive index of the modulating medium change periodically. The changes cause diffraction of the incident light, leading to diffraction losses and a decrease in the Q-factor, and the threshold for population inversion required to form a laser is very high, so laser oscillation cannot be formed. At a certain moment when the population inversion
on the upper energy level accumulates and approaches the threshold under the excitation of the optical pump, the loss of the resonant cavity is suddenly reduced, that is, the Q switch is turned on, then the Q value in the cavity increases sharply, the threshold for population inversion suddenly decreases, as a result, the accumulated
population inversion in the cavity far exceeds the threshold, allowing the stored energy to be released in an extremely short time, generating an intense laser pulse output.
The acousto-optic Q switch can modulate continuous laser into giant pulse lasers with different frequencies, different pulse widths, and different codes. It features high peak power, narrow pulse width, high repetition frequency, fast modulation speed, high on-off extinction ratio. The losses in the "off" state are extremely low, can maximize the output intensity and has excellent reliability.