Resonant grating filters have been proposed as a promising alternative to multilayer stacks for narrowband free-space filtering. The efficiency of such filters under normal incidence has been demonstrated. Unfortunately, under oblique incidence, the limited angular tolerance of the resonance forbids any filtering applications with use of standard collimated incident beams. Using a multimode planar waveguide and a bi-atom grating, we show how to increase the angular tolerance up to the divergence of standard beams (0.2 deg) without modifying the spectral bandwidth (0.1 nm), under any oblique angle of incidence.
© 2005 Optical Society of America
(050.2770) Diffraction and gratings : Gratings
(060.4510) Fiber optics and optical communications : Optical communications
(120.2440) Instrumentation, measurement, and metrology : Filters
(310.2790) Thin films : Guided waves
Anne Sentenac and Anne-Laure Fehrembach, "Angular tolerant resonant grating filters under oblique incidence," J. Opt. Soc. Am. A 22, 475-480 (2005)