Generation of 589 nm laser radiation by sum frequency of the 1064 and 1319 nm outputs of a single Nd:YAG laser

Abstract

Nonlinear optical crystals have allowed lasers to generate outputs at wavelengths other than their resonant wavelength. In particular, the generation of 589 nm laser radiation using these crystals has caught considerable attention. The 589 nm laser radiation coincides with the resonance line of the sodium D₂ transition wavelength. Therefore, these lasers are being used to make observations and measurements of the mesospheric sodium layer. With the recent developments in astronomy, a 589 nm laser has also been found useful in creating guide stars. Dye lasers have been the conventional source of 589 nm laser radiation. However, they are bulky and require frequent maintenance. In contrast, solid state 589 nm laser sources are very compact and require little maintenance. In addition to this, a solid state 589 nm laser has higher beam quality, higher reliable peak power and can be made to cover more uniformly the Doppler broadened sodium absorption profile. Most of the work on the generation of 589 nm laser radiation using solid state lasers has been on intracavity sum frequency mixing. In this paper, we report on the use of a lithium triborate (LBO) crystal in the extracavity sum frequency generation of 589 nm laser radiation using the 1064 and 1319 nm outputs of a single Nd:YAG laser.