1. YAG laser

YAG laser is a kind of solid laser based on yttrium aluminum garnet crystal.The chemical formula of yttrium aluminum garnet is Y3Al5O15, or YAG for short.

Like other solid-state lasers,YAG lasers consist of a working substance, a pumping source and a resonator.But due to the activation of doping ions in the crystal of different kinds pump sources are used and pump in a different way, adopted by the cavity structure is different, and the other functional structure of the device, YAG laser and can be divided into a variety of, for example, according to the output waveform can be divided into continuous wave frequency YAG laser, YAG laser and pulse laser, etc.;According to the working wavelength, it can be divided into 1.06 m YAG laser, frequency doubling YAG laser, Raman frequency shift YAG laser (=1.54 m) and tunable YAG laser (such as color center laser).According to doping different can be divided into Nd:YAG laser, doped Ho, Tm, Er YAG laser;According to the crystal shape, YAG laser can be divided into rod shape and plate shape.According to the output power (energy) different, can be divided into high power and small power YAG laser.

In the laser processing industry generally used 1.06 m YAG laser, according to the difference in pumping mode is divided into lamp pump YAG and semiconductor side pump YAG., in the application of laser processing system will be the pulse laser wavelength of 1064 nm after beam expander, reflection, focusing on direct radiation on the surface for processing materials, by the precise digital control, energy, and the width of laser pulse parameters such as peak power and repeating frequency, ablative material surface or make molten, through numerical control system to achieve the desired trajectory of cutting, welding, punching.

Advantages relative to fiber laser:

1. YAG crystal has a high damage threshold, which can achieve a larger monopulse energy and a higher peak power and a wider application range;

2. Cheap price. YAG laser is a kind of laser which has been developed for decades.

3, the device maintenance and replacement is relatively simple.

2、 fiber laser

Optical fiber is usually a glass solid fiber made of SiO2 as the matrix material, which is widely used in optical fiber communication. Its light guiding principle is the total internal reflection mechanism of light.Common bare fiber is generally composed of a central high-refractive index glass core (core diameter is generally 9-62.5um), a middle low-refractive index silicon glass cladding (core diameter is generally 125um), and the outermost reinforcement resin coating.

Optical fiber can be divided into single-mode fiber and multi-mode fiber.Single-mode fiber: the center glass core is relatively thin (diameter: 9um+0.5um), and it can only transmit light of one mode. The inter-mode dispersion is very small, and it has the function of self-selecting mode and limiting mode.Multi-mode fiber: The center glass core is relatively thick (50um+1um), which can transmit multiple modes of light, but its inter-mode dispersion is large, and the transmitted light is impure.

Fiber laser is refers to the element with rare earth doped glass fiber as gain medium laser, fiber laser can be developed on the basis of the optical fiber amplifier: within the optical fiber under the action of the pump are high power density, causing the laser work material laser level "population inversion", as appropriate to join the positive feedback loop (a cavity) can form a laser oscillation output.Most of the optical fiber laser devices can be realized by optical fiber, which is a product that realizes more than 95% optical path to realize the optical fiber.According to the different doped rare earth elements (Nd3+, Er3+, Yb3+, Tm3+, etc.), fiber laser can achieve different wavelengths, and ytterbium doped 1064nm fiber laser is commonly used in laser processing industry.

Advantages relative to YAG laser:

1. The advantages of miniaturization and intensification brought by the winding of optical fiber.

2. Slender fiber has a reduced volumetric area ratio, fast heat dissipation and low loss.

3. Because there is no optical lens in the resonator of the fiber laser, it has the advantages of no regulation, no maintenance and high stability, which is incomparable to the traditional YAG laser.

4. Fiber export makes the laser easily competent for various multi-dimensional arbitrary space processing applications, making the design of the mechanical system very simple.

5. Be competent for harsh working environment and have high tolerance for dust, shock, shock, humidity and temperature.

6. High electro-optic efficiency: comprehensive electro-optic efficiency is as high as 20% or more, greatly saving power consumption and operating cost.

Application:

The fiber laser consumes only 1% of the energy needed by the lantern-pumped laser and is more than twice as efficient as the semiconductor side solid state laser (Nd laser system).The combination of higher efficiency, longer service life, and less maintenance makes the cost of owning a fiber laser extremely attractive.Optical fiber lasers are of great use in laser applications that require high near infrared beam quality.They will be particularly interested in small focal spots and high power densities, such as desktop production.A 100W laser output spot can be focused to as small as 5um, which equals 109W/cm2

Fiber laser has a wide range of applications, including laser fiber communication, laser space remote communication, industrial shipbuilding, automobile manufacturing, laser engraving, laser marking, laser cutting, printing roller, metal and nonmetal drilling, cutting, welding, and fiber laser can be used as a military laser beacon light source.In naval equipment, optical fiber lasers can be used for submarine communications, torpedo detection, sea depth measurement, underwater sensing, and sea-based optical weapons.Military national defense security, medical equipment and equipment, large infrastructure and so on.