Q-switching is a laser process that uses high-intensity pulses of light energy. The laser has an internal device that affects its performance, allowing operators to control short, powerful blasts of energy. The Q-switch accumulates energy in the gain medium before releasing it, increasing light intensity rapidly. Different types of Q-switches can be used, and the pulse repetition rate and width can be adjusted for different applications, including metal cutting, dental work, laser marking, plastic surgery, and tattoo removal.
A laser that incorporates Q-switching works with pulses of light energy rather than a continuous beam. The intensity of each pulse is extremely high compared to a beam that is emitted constantly. Also known as giant pulse formation, the process creates repeating pulses when the laser is fired. A Q-switch laser has an internal device that directly affects the performance of the laser’s optical resonator, by changing its quality factor or Q-factor. By evaluating this variable, laser operators can learn how much light feedback occurs between the laser’s gain medium and the resonator, to control short, powerful blasts of laser energy.
In Q-switching, energy accumulates in the gain medium of the laser before being released. Feedback from the laser resonator is prevented at this stage and energy is stored in the gain medium until a saturation level is reached. Combined with optical amplification, this process increases light intensity so rapidly that stored energy is released and consumed almost immediately.
Within the laser, a Q-switch can be a mechanical shutter, a rotating mirror, or an optical modulator. It can also be in the form of a saturable absorbent material as is the case with a passive Q-switched laser. Q-switched lasers of this type may also incorporate a crystal or semiconductor saturable absorbing mirror. A Q-switched laser typically emits light in bursts of two nanoseconds at a time. The intensity of the pulse depends on the energy storage capacity of the gain medium and the system’s ability to prevent spontaneous emissions before maximum energy storage.
Fiber lasers and lasers using crystals and glass can all use Q-switching. Depending on the type of laser and its ability to distribute energy, the ability of the Q-switch can vary. Certain laser characteristics or combinations thereof may cause an engineer to adjust the pulse repetition rate according to the required energy level. It may also be necessary to configure the pulse width generated by the switching device, which can be done manually with an active Q-switching laser.
Applications for Q-switched lasers include metal cutting by a manufacturing company or localized dental work where fast, high-intensity laser bursts are useful. In laser marking, the Q-switch needs to be turned on and off at specific intervals that vary based on the job being performed. Lasers are also Q-switched in medical applications such as plastic surgery and tattoo removal.
Protect your devices with Threat Protection by NordVPN
