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589-nm single-frequency VECSEL for sodium guidestar applications

Here we report on the development and demonstration of a tunable high power single frequency Vertical External Cavity Surface Emitting Laser (VECSEL) operating at 589nm. A highly strained InGaAs/GaAs VECSEL designed to operate at ~ 1178nm is used in conjunction with an intracavity Birefringent Filter (BF) and low finesse Fabry-Perot (FP) etalon to achieve the single frequency operation at the fundamental wavelength. An internal non-linear optical element is then used to obtain the single frequency output at the desired wavelength of 589nm. Our results show outputs in excess of 4W at 589nm with a FWHM linewidth of the fundamental frequency to be less than 10MHz. We demonstrate the measurement of the sodium D1 and D2 lines by passing the output through a reference cell.