Planar, high NA, low loss transmitting or reflecting lenses using sub-wavelength high contrast grating

摘要

Planar lenses and reflectors are described comprising subwavelength high-contrast gratings (HCG) having high index of refraction grating elements spaced apart from one another in straight and/or curved segments and surrounded by low index material. The high-contrast grating is configured to receive an incident wave which excites multiple modes within the high-contrast grating and is focused for reflection and/or transmission by said high contrast grating. The width of the high contrast grating bars vary along a distribution direction of the grating bars which is perpendicular to the length of the grating bars and/or varies along the length of one or more grating bars to focus said reflection and/or transmission. The HCG is configured to provide double focusing, whose use is exemplified within a vertical cavity surface emitting laser (VCSEL) structure using focusing HCG structures for both the top and bottom mirrors.

主权项

1. An apparatus for focusing optical energy, comprising:
a high-contrast grating (HCG) having grating elements spaced apart from one another; said grating elements having subwavelength width and spacing and an index of refraction at or exceeding approximately 2; a material, or materials, with a low refractive index surrounding said grating elements; wherein said high-contrast grating is configured to focus for reflection and/or transmission; and wherein grating element width and spacing varies to focus said reflection and/or transmission to a desired location in relation to said high-contrast grating; wherein said high-contrast grating is configured to provide double focusing with both reflected and transmitted waves being focused.