Fabrication and testing of highly efficient resonance domain diffractive optical elements

Structuring of optical surfaces with surface-relief diffractive optical elements is an enabling technology for achieving considerable spatially varying changes in light propagation direction and wavefront curvature. This way, Bragg effects, angular and spectral selectivity and nearly 100% diffraction efficiency usually attributed to volume optical holograms can be achieved by surface relief computer generated holograms and diffractive optical elements. Several methods for fabricating deep "resonance domain" diffraction structures with periods, exceeding the subwavelength limit but near to the wavelength, were compared and optimized. Results of direct e-beam writing RIE etching, SEM and AFM measurements for fused silica gratings with period of 520 nm and groove depth of 1000 nm, designed for nearly 100% diffraction efficiency in the green 532 nm laser light, are presented.