Optical transmission control apparatus utilizing metal films perforated with subwavelength-diameter holes

A spatial light modulator having a plurality of cells and modulating the intensity of incident light as the light is transmitted through each cell of the modulator, the spatial light modulator comprising:

• a metal film having a periodic array of subwavelength-diameter holes provided therein;
• and
• a supporting layer, at least a portion of the supporting layer having a refractive index which is selectively variable for each cell, the selectively variable refractive index portion being substantially adjacent to the metal film such that the metal film and the supporting layer comprise a perforated metal film unit, and wherein selective variation of the refractive index of the selectively variable refractive index portion of the supporting layer modulates the intensity of light transmitted through the perforated metal film unit for each cell without substantially changing the direction of the light.

A tunable optical filter for modulating the intensity of incident light as the light is transmitted through the tunable optical filter, the tunable optical filter comprising:

• a metal film having a periodic array of subwavelength-diameter holes provided therein;
• and
• a supporting layer, at least a portion of the supporting layer having a selectively variable refractive index, the selectively variable refractive index portion being substantially adjacent to the metal film such that the metal film and the supporting layer comprise a perforated metal film unit, and wherein selective variation of the refractive index of the selectively variable refractive index portion of the supporting layer modulates the intensity of light transmitted through the perforated metal film unit without substantially changing the direction of the light.

A tunable optical filter having a plurality of cells and modulating the intensity of incident light as the light is transmitted through each cell of the tunable optical filter, the tunable optical filter comprising:

• a metal film having a periodic array of subwavelength-diarneter holes provided therein;
• and
• a supporting layer, at least a portion of the supporting layer having a refractive index which is selectively variable for each cell, the selectively variable refractive index portion being substantially adjacent to the metal film such that the metal film and the supporting layer comprise a perforated metal film unit, and wherein selective variation of the selectively variable refractive index portion of the refractive index of the supporting layer modulates the intensity of light transmitted through the perforated metal film unit for each cell without substantially changing the direction of the light.