Grating-coupled surface plasmon resonance on bulk stainless steel

Grating-coupled surface plasmon resonance (SPR) is demonstrated in bulk stainless steel. One-dimensional gratings were fabricated on the surface of stainless steel using imprinting combined with electrochemical etching. The extent of light coupling and the wavelengths of SPR peaks were characterized with respect to the incident angle and polarization state of the light. When the plane of incidence was orthogonal to the grating grooves, only TM polarization was absorbed at two different wavelengths. In the plane of incidence parallel to the grooves, a single resonance peak was observed only when the incident light was TE-polarized. The dependence of SPR wavelengths on the incident angle was in good agreement with theory.