Three-beam laser of 1 W single-frequency seed source laser after Yb-doped fiber amplifier (YDFA), through the beam splitter. Where a bunch of as a phase-coherent reference light. The other two beams of the first pre-entered into 200 W master oscillator power amplifier (MOPA) chain further amplification. Each MOPA chain consists of four conduction-cooled end-pumped bonded Nd: YAG lath. Output from the LDA pump light plastic of the incident to the slats at both ends of the pumping, the two ends of the slats 45 ° cutting, the oscillation of the pump light separated from the lath heat generated by the copper micro-channel cooling is taken away, amplified by 4 slats Each incident was enlarged to 9 ~ 10 kW, the last phase of the two coherent combiners. The operation mode of green laser pointer is very simple.
19 kW laser output beam quality M2 factor of 1.73. Domestic units to carry out the study of high average power slab laser North China Opto-Electronics, Shanghai Institute of Optics and Fine Mechanics, Tsinghua University, Tsinghua University, using the angular pumping of Yb: YAG / YAG composite lath structure, the kilowatt-class laser output. The structure shown in Figure 4, in which Yb: YAG crystal size of 42 mm (length) × 4 mm (width) × 1 mm (thick), each side of the bonding a 42 mm (length) × 2 mm (W) × 1 mm (thick) white YAG, and the four corners of the composite crystal cut 45 ° to inject pump light, in order to achieve the purpose of pumping several times in order to ensure the pumping light energy through the crystal medium. The operation method of 200mw laser pointer will be explained.
Of Yb: YAG crystals doped with atomic number fraction is reduced to 0.5%. The success of the lath 1016 W laser, the optical conversion efficiency of 34%. Figure 4. Angle pumping of Yb: YAG lath schematic 2.3 flakes laser sheet laser concept is proposed by the researchers of the 1994 German Aerospace Research Institute of Technical Physics, is a milestone in the history of all solid-state lasers, and its structural characteristics is: the laser medium has a large diameter / thickness ratio (10 to 50): 1]; surface pumping, surface cooling; precision optical system design, fiber-coupled output of the pump light in the crystal slice (100 to 400 mm ), many times (8 to 32), to increase their uptake (90%). This structure of the thermal gradient distribution of the direction of the laser beam propagation direction, to avoid the adverse effects caused by the thermal lens effect. If the customer wants to use the laser pointer, he or she can simple press the button on green laser pointer to turn the laser pointer on.
Moreover, thin crystals significantly reduced the reabsorption loss of Yb: YAG, thereby enhancing the conversion efficiency. Therefore, sheet laser is well suited to the needs of the development of bright, high average power. The downside is: the optical design is very complex, components, and is not conducive to the stability of the system; high-power pumping required in a small area (about tens of square millimeters) within the kilowatt-class tropical walk, its thermal The system design is very difficult. Flakes pumped lasers can be achieved by designing the face multi-pass side-pumped and mixed pumped. End-pumped structure shown in Figure 5, the sheet gain medium using some welding in the microchannel cooling heat sink, this process should be managed to avoid the stress of the flakes media introduced in the welding process. Therefore, the operation of green laser pointer is very easy.
Thin gain media face as pumping shipped and laser anti-film, the front surface mirrors plated plated two antireflection coating, the output mirror is generally spherical mirror. Pumping light incident at an angle in the gain medium, and two through the gain medium, shoot the remaining pumping light once again is reflected back into the gain medium, and so forth, pumping light repeatedly flakes media finally reached a high absorption value, the whole process pumped as even as possible, as shown in Figure 6. Figure 5 End-pumped sheet laser in Figure 6. Through coupling the pumping structure diagram Germany, Trumpf, Laser multi-way coupling to a single of Yb: YAG thin slices to obtain a continuous output of 5.3 kW laser. The manufacturer can warrant this kind of green laser pointer for a period of a year from the date of purchasing the laser pointer.
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