Electrically-tunable optical filter

1. 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; and

an electrical insulator disposed between the first conductive layer and the second conductive layer; wherein,

a change in an electrical bias between the metasurface and the second conductive layer, from a first electrical bias to a second electrical bias, tunes the electrically-tunable optical property from a first state to a second state, and changes an electrically-tunable optical filtering property of the metasurface.

2. The optical device stack of claim 1 , wherein the first conductive layer comprises indium tin oxide.

3. The optical device stack of claim 1 , wherein the array of conductive nanostructures comprises an array of nanowires.

4. The optical device stack of claim 3 , wherein the array of nanowires comprises gold nanowires.

5. The optical device stack of claim 4 , wherein the second conductive layer comprises gold.

6. The optical device stack of claim 5 , wherein the electrical insulator comprises alumina.

7. The optical device stack of claim 1 , further comprising:

a silicon nitride layer; wherein,

the second conductive layer is disposed on the silicon nitride layer and is between the silicon nitride layer and the electrical insulator.

8. The optical device stack of claim 1 , wherein:

the first electrical bias is zero volts (V); and

when the electrically-tunable optical property is tuned to the first state, the metasurface has an optical passband peak at a visible electromagnetic radiation wavelength.

9. The optical device stack of claim 8 , wherein the visible electromagnetic radiation wavelength is one of a red electromagnetic radiation wavelength, a green electromagnetic radiation wavelength, or a blue electromagnetic radiation wavelength.

10. The optical device stack of claim 8 , wherein:

when the electrically-tunable optical property is tuned to the second state, the metasurface has an optical passband peak at one of,

a different visible electromagnetic radiation wavelength than when the electrically-tunable optical property is tuned to the first state; or

a near-infrared electromagnetic radiation wavelength.

11. An optoelectronic device, comprising:

a pixel including,

a metasurface including an array of gold nanowires disposed on a layer of indium tin oxide (ITO);

a layer of gold; and

a layer of alumina disposed between the metasurface and the layer of gold;

a voltage source electrically connected to the metasurface and the layer of gold; and

a controller configured to change a voltage between the metasurface and the layer of gold by programming the voltage source.

12. The optoelectronic device of claim 11 , further comprising:

an array of pixels including the pixel, wherein multiple pixels in the array of pixels each include,

a respective metasurface including a respective array of gold nanowires disposed on a respective layer of ITO;

a respective layer of gold; and

a respective layer of alumina disposed between the respective metasurface and the respective layer of gold; and

a respective voltage source electrically connected to the respective metasurface and the respective layer of gold of each pixel in the multiple pixels.

13. The optoelectronic device of claim 12 , wherein:

the pixel is a first pixel;

the multiple pixels include a second pixel; and

the controller is configured to program respective voltage sources that are electrically connected to the first pixel and the second pixel, to apply a same voltage to the first pixel and to the second pixel at a same time.

14. The optoelectronic device of claim 12 , wherein:

the pixel is a first pixel;

the multiple pixels include a second pixel;

the controller is configured to program respective voltage sources that are electrically connected to the first pixel and the second pixel, to apply a first voltage to the first pixel and a second voltage to the second pixel at a same time; and

the first voltage is different from the second voltage.

15. The optoelectronic device of claim 12 , wherein each pixel of the multiple pixels comprises a respective photodetector positioned to receive electromagnetic radiation through a respective metasurface.

16. The optoelectronic device of claim 12 , wherein each pixel of the multiple pixels comprises a respective optical emitter positioned to emit electromagnetic radiation through a respective metasurface.

17. A method of characterizing ambient light, comprising:

receiving a first set of wavelengths of the ambient light through a metasurface while the metasurface is in a first state, the metasurface comprising an array of nanowires formed on 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 the ambient light through the metasurface while the metasurface is in the second state;

measuring a second intensity of the second set of wavelengths; and

characterizing the ambient light using at least the first intensity and the second intensity.

18. The method of claim 17 , wherein the layer of material having the electrically tunable optical property comprises indium tin oxide.

19. The method of claim 17 , further comprising:

applying at least one additional voltage to the metasurface to bias the metasurface to at least one respective additional state.

20. The method of claim 17 , further comprising:

adjusting a setting of a display responsive to the characterization of the ambient light.