Goos-Hanchen Shift in Subwavelength Gratings Enhanced by Surface Plasmon Resonance in the Infrared Range

The high sensitivity of the Goos-Hanchen angular shift for a Gaussian beam incident at an angle of surface plasmon resonance (SPR) on a metal subwavelength grating in the infrared range of the spectrum is shown. It is found that there is an optimal grating depth at which SPR occurs, and the magnitude of the angular shift increases with a decrease in the waist of the incident beam. For a focused beam incident at an angle corresponding to SPR, the zero-order diffracted beam splits into two non-overlapping beams.