Highly efficient grating-coupled surface-emitters with single outcoupling elements

We demonstrate highly efficient grating coupled surface emitting lasers with single-grating outcouplers, An outcoupling efficiency of 94% into air was achieved using a nonresonant rectangular second-order grating in combination with a multilayer reflector below the waveguide, This: resulted in an external differential quantum efficiency as high as 50%, comparable to that of conventional edge-emitting lasers, limited by absorptive loss in the passive grating sections, The lasers have separated oscillators and outcouplers, which facilitates the fabrication of sur;face emitters that possess beam-shaping capabilities through holographic wavefront conversion.