Resonance tunable optical filter - US 6738194 B1
An optical modulating device capable of use as a light valve, display, or optical filter, which uses variation in incident angle to exploit color-selective absorption at a metal-dielectric interface by surface plasmons. The device includes a dielectric layer, at least one metallic layer through which electromagnetic radiation may be transmitted or reflected, and incident and exit layers which are both optically transmissive. A beam steering mechanism controls the incident angle of the electromagnetic radiation. In one embodiment, an external beam steering mechanism is used to set the incident light angle onto the filter. In another embodiment, the filter is formed as an integral part of, for example, a cantilever. The incident light angle is then controlled by the angle of the filter cantilever.