Polarization dependence of optical properties of metallodielectric gratings with subwavelength grooves in classical and conical mounts

We report optical transmission and reflection spectral measurements in the visible and near infrared on a one-dimensional transmission grating having a metal film deposited on deep rectangular subwavelength grooves etched in quartz. Measurements are made for both classical and conical diffraction geometry by varying the azimuthal angles (phi) between the plane of incidence and the grating vector. Strong differences for transverse electric (TE) and transverse magnetic (TM) polarized light are seen. We find conditions under which the transmission is negligible irrespective of light polarization and angle of incidence. The transmission spectra show deep dips corresponding to excitation of surface plasmons by TM polarized light when phi=0 degrees, by both TE and TM light when 0 degrees < 90 degrees and by TE light for phi=90 degrees. We also examine the reciprocity behavior of the optical properties for incidence from the metal and substrate sides and dependence on light polarization. (C) 2008 American Institute of Physics.