Comprehensive analysis of diffraction efficiency of conical beam from sub-wavelength binary metallic grating using rigorous coupled-wave theory

Abstract

Rigorous coupled-wave theory has been implemented to study comprehensively diffraction efficiency of binary metallic gratings. We have investigated diffraction efficiency for TE and TM polarizations and conical incident beam in more detail than the other reported studies. As a general case, we study diffraction efficiency with respect to incident angles and grating period. Calculated first-order diffraction efficiencies for one-dimensional binary metallic gratings have been shown to converge to the correct value with an effect of increasing number of space harmonics over a wide range of grating depth. More field number of space harmonics is shown to be required for the convergence of gratings with larger grating periods, deeper gratings, TE and TM polarization, and conical diffraction.