Mass-transport fabrication of off-axis and prismatic gallium phosphide optics

Refractive prismatic and off-axis micro-optical elements have been fabricated in gallium phosphide by mass-transport smoothing of multistep and binary preforms, respectively. A total optical efficiency of greater than 94% was measured for the prism, while diffraction-limited collimation and steering were demonstrated with the off-axis lens. A qualitative discussion of possible errors in binary preform etching and their effects on the surface figure is also included.