ABSTRACT
Diffraction of light of a visible spectral range by subwavelength metal gratings has been investigated experimentally and theoretically using rigorous electromagnetic calculations. It has been demonstrated that an effect of surface plasmon resonance (SPR), at which total absorption of light by metal grating can be observed, occurs under certain conditions. Large positive and negative Goos-Hänchen (GH) shifts occur near the SPR. It has been shown that the reflected beam is split into two parts, the relative powers of which depend on the incident beam width and the grating depth. The dependence of the GH shifts on the grating period and grating depth has been investigated for different incident beam widths. The high sensitivity of the GH shift on the incident angle of a light beam near the SPR has been demonstrated.
ABSTRACT
A high-efficiency subwavelength diffractive beam combiner operating in a visible spectral range is designed, fabricated, and demonstrated. Such a device combines red, green, and blue color beams into one output light beam. Diffraction efficiencies of different types of gratings are calculated for various materials, incidence angles, and polarizations of light. It is shown that the plasmon resonance via a grating coupling occurs at the determined conditions. Subwavelength gratings with a period of 400 nm are fabricated and tested using laser and laser diode sources.
