Low Etendue Yellow-Green Solid-State Light Generation by Laser-Pumped LuAG:Ce Ceramic

A low Etendue (6.1 mm(2)) yellow-green solid-state light source with optical conversion efficiency up to 101.3 lumen/Watt is demonstrated by through high-power laser diode pumping of a static LuAG:Ce transparent ceramic plate. A 443-nm blue laser diode array with a full-width-half-maximum (FWHM) of <1.5 nm and a maximum output power of 15.2 W is used to attain a high spectral absorption efficiency. The output from the high-power laser diode array is collimated, shaped, despeckled, and focused to display a Gaussian-like profile with a 1.5-mm beam waist (1/e(2) radius) to stimulate a 1.2-mm thick LuAG:Ce transparent ceramic plate with an emission FWHM spectra at 505-585 nm. No thermal quenching, pump absorption saturation, and obvious luminous flux decrease is found during test.