Surface plasmon resonance based integrable micro spectrometer

We propose and realize the concept of a surface plasmon resonance based integrable and planar micro spectrometer that is suitable to determine the wavelength of incident light with sub-nanometer resolution over a broad range of frequencies in the infrared, visible, and ultraviolet regime. A dielectric grating structure with an ascending effective refractive index in the direction perpendicular to the periodicity is applied on top of a 20 nm thick gold film. Monochromatic light in normal incidence excites surface plasmons at confined areas on the sample so that the transmission is reduced locally. Depending on the wavelength, this area of low transmission shifts along the grating. The spatial transmission pattern provides information on the wavelength of the incident light.