Enhancement of second harmonic generation in DPSS laser

Abstract

High-power diode-pumped compact visible lasers have attracted much attention. A diode-pumped solid-state laser (DPSSL) with high efficiency, high output power, a good spatial beam profile, and good stability is highly desired for use in a lot of applications such as material processing holography, range finding, target illumination and designation, satellite and lunar ranging, thermonuclear fusion, plasma experiments, and in general for scientific work requiring high power densities such as pumping other laser crystals. Laser diode with 808 nm wavelength is the key component in the development of diode pumped solid state laser (DPSSL). Much higher pumping intensity can be achieved using laser diodes instead of flashlamps as pump sources for solid-state lasers because of laser diode high spatial and spectral brightness. The main advantages of diode lasers over flashlamps as pump sources are overall laser efficiency and extended pump-source lifetime. The increase in efficiency is due to improved use of the optical pump radiation. Solid state laser like Nd:YVO4 has optical absorption only in relatively narrow wavelength bands; thus only small portion of the broadband flashlamp energy passes can be absorbed and the rest just passing through the material without being absorbed. On the other hand, diode laser output is narrowband; thus most of it is absorbed and utilized.