With the aim of reducing surface reflections and increasing the diffraction efficiency we investigated the superposition of subwavelength phase gratings onto blazed phase gratings. With direct-write electron-beam lithography bare blazed gratings and blazed gratings carrying subwavelength gratings were fabricated and their optical performances compared. For TE polarization the subwavelength-carrying gratings showed a maximum diffraction efficiency of 90.6%, whereas the corresponding maximum value for the bare grating was 86.3%. The experiment was simulated with rigorous diffraction theory.
© 2000 Optical Society of America
(220.4000) Optical design and fabrication : Microstructure fabrication
Original Manuscript: November 30, 1999
Revised Manuscript: May 5, 2000
Published: September 10, 2000
Fredrik Nikolajeff, Björn Löfving, Mathias Johansson, Jörgen Bengtsson, Sverker Hård, and Claus Heine, "Fabrication and simulation of diffractive optical elements with superimposed antireflection subwavelength gratings," Appl. Opt. 39, 4842-4846 (2000)