Q-switched laser

A Q-switched laser is a laser that uses active or passive Q-switching technology to release high-energy pulses of light. Typical applications of such lasers are in product processing (e.g., cutting, drilling, laser noting). Pumping nonlinear regularity conversion tools, ranging, and remote noticing.

Q-switched lasers can be continually pumped or pulsed pumped, for instance, from a flash lamp (particularly for low pulse rep prices). For constant pumping, the gain tool must have a long top energy state lifetime to attain adequately high stored energy without shedding energy as fluorescence does. The saturation power need not be as low, as this would certainly trigger the gain to be also big, making it harder to reduce an early laser. The last issue is particularly likely to occur with fibre lasers. On the other hand, high saturated injection quantities can make reliable energy extraction difficult.

Kind of Q-switched laser

Actively Q-switched solid-state laser

One of the most common kind is an active Q-switched solid-state laser. Solid state gain media have good power storage space abilities. Quantity lasers enable huge setting areas (thus greater pulse power and peak power) and much shorter laser resonators (compared to fibre lasers, for example). The laser resonator consists of an energetic Q switch - a light modulator, generally an acoustic-optical Q switch.

For wavelengths in the 1μm spectral array, one of the most typical pulsed lasers are based upon neodymium-doped laser crystals, such as Nd: YAG, Nd: YVO4, or Nd: YLF, although ytterbium-doped laser gain media can additionally be made use of. A low pulse rep rate (less than the inverse upper power state lifetime) can attain the highest possible pulse power and the fastest pulse period at the expense of minimized average output power. A bigger Nd: YAG laser with a 10-watt pump resource, such as a diode rod, can accomplish a pulse power of numerous millijoules. Nd: YVO4 is ideal for brief pulse durations and high pulse rep prices or low-pump power procedures. Q-switched lasers with longer exhaust wavelengths are generally based on erbium-doped laser gain media.

Passive Q-switched laser

The passive Q-switched laser contains a saturated absorber (passive Q-switch) rather than a modulator. Regular pulse sequences can be obtained for continuous pumping where the timing of the pulses can not typically be controlled by external means. And the pulse repetition rate increases as the pump power increase. Cr: YAG crystal is one of the most generally utilized saturable absorbers for 1-μm lasers.

Passive Q-switched microchip lasers have particularly compact Setups. Such lasers typically give off power pulses varying from a nanojoule to a few microjoules. With a typical power outcome of 10s of milliwatts and repetition prices varying from a couple of kilohertz to a few megahertz.

Cr: YAG crystal

Cr: YAG crystal is a very excellent passive Q switching product with numerous benefits, such as easy-to-achieve high pulse repeating price and also peak outcome power, reduced saturation light intensity, high doping concentration, large absorption cross-section, no degradation sensation, secure photochemical properties, high damage threshold, long life, easy to use, good thermal conductivity.

The difference between passive as well as active Q-switched lasers

The average result power of passively Q-switched lasers is much more limited than that of active Q-switched lasers since the saturable absorber dissipates some power, thus restricting thermal effects. Note that saturable absorbers typically have unsaturated losses, increasing dissipated energy beyond what is inevitable.
Specifically, some smaller-sized Q-switched lasers and lasers with longer resonators containing an optical filter, such as a volumetric Bragg grating, operate in a uniaxial resonator mode. This causes a tidy time shape and a small optical bandwidth, which is generally limited by pulse duration. Various other lasers oscillate in multiple cavity modes, which causes a mode-jumping result: the optical power is modulated to a regularity that is an integer multiple of the cavity round-trip regularity.

Application of Q-switched laser

Q - switched laser has a wide variety of applications. Some examples:

1. Laser product processing, such as laser cutting, laser boring, laser noting, laser pattern

2. Laser rangefinder

3. Lidar for 3D imaging

4. Laser-induced breakdown spectrum

5. Medical applications, such as dermatology as well as tattoo elimination

6. Nonlinear regularity conversion pumping devices, such as pulsed optical parametric oscillators

7. Fluorescence spectrum