Laser action with low threshold average pump power density (similar to 50 W. cm(-2)) at room temperature is reported for a crack-free planar vertical cavity surface emitting laser (VCSEL) structure based on a bottom lattice-matched AllnN/GaN distributed Bragg reflector (DBR) and a top dielectric DBR. The cavity region, formed by n- and p-type GaN layers surrounding only three InGaN/GaN quantum wells, corresponds to a typical active region suitable for an electrically driven VCSEL. In addition to low threshold, a spontaneous emission coupling factor beta 2 x 10(-3) is derived for this ready-to-be-processed laser structure.
Tobias Kippenberg, Anat Siddharth
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