High-efficiency binary fan-out gratings by modulation of a high-frequency carrier grating.
A modulation scheme that uses pulse-position modulation of a high-frequency binary grating to increase the diffraction efficiency of the elements is presented. These elements are designed and fabricated with both one- and two-dimensional signals for operation in transmission or reflection modes in the visible and the infrared regions of the spectrum. A direct electron-beam lithography fabrication process capable of realizing features of ∼280 nm with a resolution of 15 nm is described in detail. Experimental results show that diffraction efficiencies of >80% are attainable.
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P
Blair
M R
MR
Taghizadeh
W
W
Parkes
C D
CD
Wilkinson