Proceedings Article | 12 October 2005
Proc. SPIE. 5970, Photonic Applications in Devices and Communication Systems
KEYWORDS: Mirrors, Crystals, Semiconductor lasers, Laser resonators, Sapphire, Thermal effects, Laser crystals, Disk lasers, Diode pumped solid state lasers, Absorption
The key point to scale the output power of diode-pumped solid-sate (DPSS) laser is to solve the thermally induced problems such as fracture of the material by thermal stress, degradation of the beam quality and efficiency by thermally induced birefringence and aberration of the thermal lens, etc. For end-pumped solid state lasers, the gain medium can be constructed in a format of a thin disk or a composite rod to scale the output power. This concept has been successfully used to scale DPSS laser output powers by 1~2 order, depending on the laser material and the beam quality of the output. In a thin disk laser, pump induced heat flows predominantly along the thickness of the laser disk and the thermal lens is eliminated to first order. However, a conventional thin disk laser requires a complex and expensive multipass pump setup to maximize pump absorption for the thinnest crystal possible to minimize the residual thermal lens. Alternatively, using a composite rod in a conventional end-pumped DPSS laser elevates the maximum allowable pump power by
~50%, since the interface between the doped and undoped region of the gain medium provides a heat buffering effect and the maximum thermal stress is reduced. Our anvil-cell disk laser, which clamps the gain medium between the heat sink and a sapphire window, combines the benefits of both the thin-disk laser and lasers using composite rods but with the ability to further optimize material properties. In addition, the portion of thermal lens due to bulge of the gain
medium can be compensated by pressure tuning. The complexity and cost on pump setup can be greatly reduced with this relatively simple design. In this work we demonstrated a reliable high power Nd:YVO<sub>4</sub> laser which delivered 26.2 W of laser output at M<sup>2</sup>=3. Results of intracavity frequency doubling with this laser are also reported.
