Laser Applications and Classification

1.disc laser

The proposal of the Disk Laser design concept effectively solved the thermal effect problem of solid-state lasers and achieved the perfect combination of high average power, high peak power, high efficiency, and high beam quality of solid-state lasers. Disk lasers have become an irreplaceable new laser light source for processing in the fields of automobiles, ships, railways, aviation, energy and other fields. The current high-power disc laser technology has a maximum power of 16 kilowatts and a beam quality of 8 mm milliradians, which enables robot laser remote welding and large-format laser high-speed cutting, opening up broad prospects for solid-state lasers in the field of high-power laser processing. Application market.

Advantages of disc lasers:

1. Modular structure

The disc laser adopts a modular structure, and each module can be quickly replaced on site. The cooling system and light guide system are integrated with the laser source, with compact structure, small footprint and fast installation and debugging.

2. Excellent beam quality and standardized

All TRUMPF disc lasers over 2kW have a beam parameter product (BPP) standardized at 8mm/mrad. The laser is invariant to changes in operating mode and is compatible with all TRUMPF optics.

3. Since the spot size in the disc laser is large, the optical power density endured by each optical element is small.

The damage threshold of optical element coating is usually about 500MW/cm2, and the damage threshold of quartz is 2-3GW/cm2. The power density in the TRUMPF disk laser resonant cavity is usually less than 0.5MW/cm2, and the power density on the coupling fiber is less than 30MW/cm2. Such a low power density will not cause damage to optical components and will not produce nonlinear effects, thus ensuring operational reliability.

4. Adopt laser power real-time feedback control system.

The real-time feedback control system can keep the power reaching the T-piece stable, and the processing results have excellent repeatability. The preheating time of the disc laser is almost zero, and the adjustable power range is 1%–100%. Since the disc laser completely solves the problem of thermal lens effect, the laser power, spot size, and beam divergence angle are stable within the entire power range, and the wavefront of the beam does not undergo distortion.

5. The optical fiber can be plug-and-play while the laser continues to run.

When a certain optical fiber fails, when replacing the optical fiber, you only need to close the optical path of the optical fiber without shutting down, and other optical fibers can continue to output laser light. Optical fiber replacement is easy to operate, plug and play, without any tools or alignment adjustment. There is a dust-proof device at the street entrance to strictly prevent dust from entering the optical component area.

6. Safe and reliable

During the processing, even if the emissivity of the material being processed is so high that laser light is reflected back into the laser, it will have no effect on the laser itself or the processing effect, and there will be no restrictions on material processing or fiber length. The safety of laser operation has been awarded the German safety certificate.

7. The pumping diode module is simpler and faster

The diode array mounted on the pumping module is also of modular construction. Diode array modules have a long service life and are warranted for 3 years or 20,000 hours. No downtime is required whether it is a planned replacement or an immediate replacement due to a sudden failure. When a module fails, the control system will alarm and automatically increase the current of other modules appropriately to keep the laser output power constant. The user can continue to work for ten or even dozens of hours. Replacing pumping diode modules at the production site is very simple and requires no operator training.

2.2 Fiber laser

Fiber lasers, like other lasers, are composed of three parts: a gain medium (doped fiber) that can generate photons, an optical resonant cavity that allows photons to be fed back and resonantly amplified in the gain medium, and a pump source that excites photon transitions.

Features: 1. Optical fiber has a high “surface area/volume” ratio, good heat dissipation effect, and can work continuously without forced cooling. 2. As a waveguide medium, optical fiber has a small core diameter and is prone to high power density within the fiber. Therefore, fiber lasers have higher conversion efficiency, lower threshold, higher gain, and narrower linewidth, and are different from optical fiber. Coupling loss is small. 3. Because optical fibers have good flexibility, fiber lasers are small and flexible, compact in structure, cost-effective, and easy to integrate into systems. 4. Optical fiber also has quite a lot of tunable parameters and selectivity, and can obtain a quite wide tuning range, good dispersion and stability.


Fiber laser classification:

1. Rare earth doped fiber laser

2. Rare earth elements doped in currently relatively mature active optical fibers: erbium, neodymium, praseodymium, thulium, and ytterbium.

3. Summary of fiber stimulated Raman scattering laser: Fiber laser is essentially a wavelength converter, which can convert the pump wavelength into light of a specific wavelength and output it in the form of laser. From a physical point of view, the principle of generating light amplification is to provide the working material with light of a wavelength that it can absorb, so that the working material can effectively absorb energy and be activated. Therefore, depending on the doping material, the corresponding absorption wavelength is also different, and the pump The requirements for wavelength of light are also different.

2.3 Semiconductor laser

Semiconductor laser was successfully excited in 1962 and achieved continuous output at room temperature in 1970. Later, after improvements, double heterojunction lasers and stripe-structured laser diodes (Laser diodes) were developed, which are widely used in optical fiber communications, optical discs, laser printers, laser scanners, and laser pointers (laser pointers). They are currently the The most produced laser. The advantages of laser diodes are: high efficiency, small size, light weight and low price. In particular, the efficiency of the multiple quantum well type is 20~40%, and the P-N type also reaches several 15%~25%. In short, high energy efficiency is its biggest feature. In addition, its continuous output wavelength covers the range from infrared to visible light, and products with optical pulse output up to 50W (pulse width 100ns) have also been commercialized. It is an example of a laser that is very easy to use as a lidar or excitation light source. According to the energy band theory of solids, the energy levels of electrons in semiconductor materials form energy bands. The high energy one is the conduction band, the low energy one is the valence band, and the two bands are separated by the forbidden band. When the non-equilibrium electron-hole pairs introduced into the semiconductor recombine, the released energy is radiated in the form of luminescence, which is the recombination luminescence of carriers.

Advantages of semiconductor lasers: small size, light weight, reliable operation, low power consumption, high efficiency, etc.

2.4 YAG laser

YAG laser, a type of laser, is a laser matrix with excellent comprehensive properties (optics, mechanics and thermal). Like other solid lasers, the basic components of YAG lasers are laser working material, pump source and resonant cavity. However, due to different types of activated ions doped in the crystal, different pump sources and pumping methods, different structures of the resonant cavity used, and other functional structural devices used, YAG lasers can be divided into many types. For example, according to the output waveform, it can be divided into continuous wave YAG laser, repeated frequency YAG laser and pulse laser, etc.; according to the operating wavelength, it can be divided into 1.06μm YAG laser, frequency doubled YAG laser, Raman frequency shifted YAG laser and tunable YAG laser, etc.; according to doping Different types of lasers can be divided into Nd:YAG lasers, YAG lasers doped with Ho, Tm, Er, etc.; according to the shape of the crystal, they are divided into rod-shaped and slab-shaped YAG lasers; according to different output powers, they can be divided into high power and small and medium power. YAG laser, etc.

The solid YAG laser cutting machine expands, reflects and focuses the pulsed laser beam with a wavelength of 1064nm, then radiates and heats the surface of the material. The surface heat diffuses to the interior through thermal conduction, and the width, energy, peak power and repetition of the laser pulse are precisely controlled digitally. Frequency and other parameters can instantly melt, vaporize and evaporate the material, thereby achieving cutting, welding and drilling of predetermined trajectories through the CNC system.

Features: This machine has good beam quality, high efficiency, low cost, stability, safety, more precision, and high reliability. It integrates cutting, welding, drilling and other functions into one, making it an ideal precision and efficient flexible processing equipment. Fast processing speed, high efficiency, good economic benefits, small straight edge slits, smooth cutting surface, large depth-to-diameter ratio and minimum aspect-to-width ratio thermal deformation, and can be processed on various materials such as hard, brittle, and soft. There is no problem of tool wear or replacement in processing, and there is no mechanical change. It is easy to realize automation. It can realize processing under special conditions. The pump efficiency is high, up to about 20%. As the efficiency increases, the heat load of the laser medium decreases, so the beam is greatly improved. It has long quality life, high reliability, small size and light weight, and is suitable for miniaturization applications.

Application: Suitable for laser cutting, welding and drilling of metal materials: such as carbon steel, stainless steel, alloy steel, aluminum and alloys, copper and alloys, titanium and alloys, nickel-molybdenum alloys and other materials. Widely used in aviation, aerospace, weapons, ships, petrochemical, medical, instrumentation, microelectronics, automobile and other industries. Not only the processing quality is improved, but also the work efficiency is improved; in addition, the YAG laser can also provide an accurate and fast research method for scientific research.


Compared to other lasers:

1. YAG laser can work in both pulse and continuous modes. Its pulse output can obtain short pulses and ultra-short pulses through Q-switching and mode-locking technology, thus making its processing range larger than that of CO2 lasers.

2. Its output wavelength is 1.06um, which is exactly one order of magnitude smaller than the CO2 laser wavelength of 10.06um, so it has high coupling efficiency with metal and good processing performance.

3. YAG laser has compact structure, light weight, easy and reliable use, and low maintenance requirements.

4. YAG laser can be coupled with optical fiber. With the help of time division and power division multiplex system, one laser beam can be easily transmitted to multiple workstations or remote workstations, which facilitates the flexibility of laser processing. Therefore, when selecting a laser, you must consider various parameters and your own actual needs. Only in this way can the laser exert its maximum efficiency. Pulsed Nd:YAG lasers provided by Xinte Optoelectronics are suitable for industrial and scientific applications. Reliable and stable pulsed Nd:YAG lasers provide pulse output up to 1.5J at 1064nm with repetition rates up to 100Hz.


Post time: May-17-2024