Investigation of inverse polarization transmission through subwavelength metallic gratings in deep ultraviolet band

Inverse polarization transmission of light, with the TE transmittance ηTE largely exceeding the TM transmittance ηTM, through subwavelength metallic gratings at certain wavelength in deep ultraviolet band is theoretically investigated. By using the Fourier modal method and the planar waveguide theory, we show that the light transmission involves both the surface plasmon and the low-loss waveguide modes. Strong coupling of the incident wave to surface plasmon polariton results in the minimum in TM transmittance, whereas the coupling to the low-loss mode leads to the TE transmittance maximum. The established physical mechanism is sufficient to explain the inverse polarizing phenomenon observed in aluminum grating at the wavelength of 193 nm, which may lead to important applications such as effective and compact polarizer used in DUV lithography.