Bragg holograms with binary synthetic surface-relief profile.

Synthetic pulse-position-modulated binary surface-relief elements with subwavelength transverse features are designed by using a combination of scalar and rigorous electromagnetic diffraction theories. Theoretically, both reflection- and transmission-type elements achieve nearly 100% diffraction efficiency at Bragg incidence. Using direct-write electron-beam lithography and reactive ion etching, we demonstrate a reflective binary Bragg-type multiple beam splitter for operation at lambda = 1.064 microm.