Semiconductor double-end pumping solid laser

Abstract

A solid laser of semiconductor double -end surface pumping consists of two laser diodes, two pieces of optical fibers, two sets of optical coupling units, two gain medias, ( 1 / 2 ) lambda wave plate, cooling unit and output mirror. It is featured as making light outputted by gain media be linear polarized light with different heat expansion coefficient at different axial direction, setting two gain medias in position of relative 90 degree for forming co focal system with heat lens generated by two gain medias and cooling all surfaces of gain media by cooling unit.

Description

Technical field [0001] The invention relates to a semiconductor end-pumped solid-state laser. Background technique [0002] End-pumped solid-state lasers pumped by laser diodes are popular because of their compact devices, good beam quality, and high efficiency. There are no reports of end-pumped laser products with a power exceeding 26W in China, and only spectrophysics etc. A handful of laser companies can do it. [0003] Among the many laser crystals suitable for laser diode pumping, Nd:YVO4 crystals are favored by people because of their large laser emission cross-section, wide absorption spectrum, and polarization output ("LD pumping high-efficiency Nd for femtosecond ultraviolet laser generation : YVO4 Green Laser Research", Acta Photonica Sinica, 2000, 29(11): 1053-1055). However, the thermal conductivity of Nd:YVO4 crystal is poor, only half of that of YAG, and it will produce obvious thermal lens effect when pumped with high power; at the same time, because Nd:YVO...

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Problems solved by technology

[0005] To overcome the longitudinal thermal effect, the axisymmetric heat dissipation method is adopted, that is, the two surfaces perpendicular to the "c" axis of the Nd:YVO4 crystal are cooled, while the two sides of the "a" axis are not cooled ("Diode Pumped Laser with Strongthermal Lens Crystal", US Patent, Patent No. US 5410559), this method can be used to obtain a circular spot output when pumping at low power, but if a high-power laser diode is selected as the pumping source of Nd:YVO4, because a large amount of heat on the Nd:YVO4 crystal cannot be used in time Spread out so that the output laser spot is elliptical, and in severe cases, it will damage the crystal

[0006] In addition, since the thermal stress generated by the thermal effect in the crystal cannot exceed the limit of the fracture stress of the Nd:YVO4 crystal, the maximum pumping power and output power per unit area of ​​the gain medium are limited ("Power scaling of diode-pumped Nd :YVO4 Lasers", IEEE JQuantum Electronics, 2002, 38(9): P1291~1299)

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