Polarization properties of a periodically-modulated metal film in regions of anomalous optical transparency

We present an analytical treatment of the resonance optical effects in which an arbitrarily polarized wave is incident at an arbitrary angle onto a periodically-modulated metal film in the conical mount. We show that under enhanced light transmittance conditions, not only intensity, but also the polarization of both reflected and transmitted waves undergoes significant changes. An in-depth investigation of the polarization transformation including the polarization conversion for both zeroth and nonzeroth diffraction orders is carried out. Besides, we derive novel polarization reciprocity relations.

Figure 1

(Color online) Diffraction on the periodically-modulated metal film. The resonance occurs at the metal-superstrate interface in the $r\text{th}$ diffraction order, $k_{rt}=K^{-}$.

Figure 2

(Color online) Polarization dependence upon the SPP tilting angle for the single-order resonance, $r=1$, in the harmonically modulated film. The film thickness and the dimensionless grating vector are ${\Phi }^{\prime }=3$, $g∕k=1.2K_{-}$, ${\xi }_0=0.133i+0.00071$ (Ag at $1.06\mu \mathrm{m}$). (a) corresponds to zeroth-order transmittance and/or reflectance under DB resonance for ${\epsilon }_{-}={\epsilon }_{+}=1$, ${\tilde{\xi }}_{\pm 1}=2.65i\sqrt{{\xi }_0^{\prime }}$. Circular (triangular) symbols correspond to ${\mid T_0^{+\mid +-}\mid }^2$ $\left({\mid T_0^{-\mid +-}\mid }^2\right)$ numerically simulated dependency. Small symbols are for a LR mode, big ones are for a SR mode. Curves are the normalized ${\sin }^2\left(2{\psi }_{10}\right)$. (b) corresponds to nonzeroth-order transmittance under SB resonance for ${\epsilon }_{-}=1$, ${\epsilon }_{+}=2.31$ (quartz), ${\tilde{\xi }}_{\pm 1}=1.25i\sqrt{{\xi }_0^{\prime }}$. Circular (triangular) symbols correspond to ${\mid T_1^{+\mid --}\mid }^2$ $\left({\mid T_1^{+\mid -+}\mid }^2\right)$ numerically simulated dependency. Solid [dashed] curve is the normalized squared $\cos \theta \sin \left({\psi }_{10}\right)\left[\cos \left({\psi }_{10}\right)\right]$.