Monolithic integration of continuous-relief diffractive structures with Vertical-cavity surface-emitting lasers

In this work, we have studied the transfer of diffractive optical elements (DOEs), originally made in resist, into GaAs for monolithic integration with vertical-cavity surface-emitting lasers (VCSELs). The DOEs are blazed gratings and Fresnel lenses, and have been fabricated on the back surface of bottom emitting VCSELs using electron-beam lithography or replication by hot embossing in resist followed by a quick-dry etch step. Diffraction efficiency was measured to be 81% in the first order of diffraction for the blazed grating.