Vertical-cavity surface-emitting lasers with semitransparent metallic mirrors and high quantum efficiencies

Semitransparent thin silver films are employed as both the top mirrors and electrodes for GaAs vertical-cavity surface-emitting lasers. The semitransparent silver films allow the emission of light from the top epitaxial side. Quarter-wave AlAs/AlxGa1−xAs stacks are used as the bottom n-type mirrors. Light output versus excitation current measurements yields an efficiency of 0.76 mW/mA from the top silver mirror side, which corresponds to an external differential quantum efficiency of 54% at a lasing wavelength of 0.88 μm. The internal differential quantum efficiency is estimated to be ≳94%. An optical output power of 10 mW is obtained at a pulsed excitation current of 72 mA.