Controlling phase response in a sub-wavelength grating lens

摘要

A sub-wavelength grating device having controlled phase response includes a grating layer having line widths, line thicknesses, line periods, and line spacings selected to produce a first level of control in phase changes of different portions of a beam of light reflected from the grating layer. The device also includes a substrate affixed to the grating layer that produces a second level of control in phase changes of different portions of a beam of light reflected from the grating layer, the second level of control being accomplished abrupt stepping of the substrate in a horizontal dimension, ramping the substrate in a horizontal dimension, or changing the index of refraction in a horizontal dimension.

主权项

1. A sub-wavelength grating device having a controlled phase response, comprising:
a grating layer having line widths, line thicknesses, line periods, and line spacings selected to produce a first level of control in phase changes of different portions of a beam of light incident on the sub-wavelength grating device; and a substrate affixed to the grating layer that produces a second level of control in the phase changes of the different portions of the beam of light, the second level of control being accomplished by changing an index of refraction of the substrate in the horizontal dimension, wherein the index of refraction of the substrate is modified in a substantially continuous manner along the horizontal dimension.