We have fabricated subwavelength diffractive optical elements with binary phase profiles for operation at 975 nm. The individual surface-relief features of the elements are smaller than the wavelength of light in the material. By modulating the size and spacing of the features we form artificial, gradient, effective index-of refraction surfaces. The blazed transmission gratings were designed with rigorous coupled-wave analysis and fabricated by direct-write electron-beam lithography and reactive ion-beam etching in GaAs. The gratings have minimum features 63 nm wide. Transmission measurements show 85% diffraction efficiency into the first order.
© 1995 Optical Society of America
Original Manuscript: February 27, 1995
Published: June 15, 1995
M. E. Warren, R. E. Smith, G. A. Vawter, and J. R. Wendt, "High-efficiency subwavelength diffractive optical element in GaAs for 975 nm," Opt. Lett. 20, 1441-1443 (1995)