A compact diode-pumped microchip green light source with a built-in thermoelectric element

Abstract

A diode-pumped microchip green light source which was based upon a diffusion-bonded Nd:YVO(4)/KTiOPO(4) composite crystal and had a built-in thermoelectric element was developed. The source had the small volume of 0.7 cm(3) and showed the average green power of up to 25 mW and the average electrical power consumed in the thermoelectric element of 15 mW at the interior temperature of 51 degrees C, under the driving condition of the duty ratio of 50%, the average electrical power consumed in pump diode of about 304 mW, and the ambient temperature of 20 degrees C, which resulted in the electrical-to-optical conversion efficiency of up to 7.8%. The power of the source was so stable with the fluctuation of less than 0.2%. Our source is the smallest green laser with the built-in temperature-controlling unit to our knowledge and thought to be useful in many applications including the portable laser display system. (C) 2008 The Japan Society of Applied Physics.