Subwavelength-Structured Surfaces for Optical Interconnects

摘要

The fabrication of sub-wavelength structures has been used to develop efficientdiffractive optical elements with a single mask/etch step as well as optically absorptive areas. By the controlled removal of a substrate material in sub-wavelength units, the effective refractive index of the substrate material can be varied from the original index to that of air or other fill material. Diffractive elements can be fabricated by varying the substrate refractive index in a diffractive pattern. A linear grating and a spherical diffractive lens were fabricated in fused quartz for use at the 632.8mm wavelength. A technique for fabricating sub-micron structures in silicon was also developed. The micro-structures have reflectances of as low as 0.05% and less than 0.5% across the visible spectrum. These structures can be used as antireflection coatings in silicon-based optoelectronic systems.