Electrically-tunable optical filter

A method of measuring light, comprising:

• receiving a first set of wavelengths of light through a metasurface while the metasurface is in a first state, the metasurface comprising an array of nanostructures and a layer of material having an electrically-tunable optical property;
• measuring a first intensity of the first set of wavelengths;
• applying a voltage to the metasurface to bias the metasurface to a second state different from the first state;
• receiving a second set of wavelengths of light through the metasurface while the metasurface is in the second state;
• and
• measuring a second intensity of the second set of wavelengths.

An optical device stack, comprising:

• at least one of a photodetector or an optical emitter;
• a metasurface disposed over at least one of a light-receiving surface of the photodetector or a light emission surface of the optical emitter and including,
• a first conductive layer having an electrically-tunable optical property;
• and
• an array of conductive nanostructures disposed on a first side of the first conductive layer;
• a second conductive layer disposed on a second side of the first conductive layer, over at least one of the light-receiving surface of the photodetector or the light emission surface of the optical emitter;
• and
• an electrical insulator disposed between the first conductive layer and the second conductive layer.