Switching capability of double-sided grating with horizontal shift

A TiO2 grating beam splitter on the SiO2 layer is designed using the modal analysis. Normal incident light couples to the -1st/+1st-order transmission diffraction with a 49.6% efficiency for each and with a 50 refraction angle that is larger than the critical angle for the SiO2-air interface. The SiO2 interlayer is sandwiched between the two gratings. The finite-integration-technique investigation shows its switching capability due to the quarter-period shift between the gratings, with the zeroth-order transmission smaller than 5% for the off state and larger than 95% for the on state from 553 to 654 nm wavelength regime. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3476349]