Plasmonic metasurface light filter and imaging sensor including light filter

An imaging sensor comprising:

• an array of pixels;
• a plasmonic metasurface color light filter positioned between the array of pixels and an imaging target, wherein the plasmonic metasurface comprises a planar array of red, green and blue unit cells defining a pixelated color filter, each unit cell of the color filter corresponding in size and position to a pixel of the imaging sensor, the planar array of unit cells being places over the imaging sensor whereby each of the unit cells aligns with a pixel of the imaging sensor,
• wherein each unit cell includes a plurality of light-transmissive nanoholes having a non-circular substantially elliptical cross-section, each unit cell being individually tunable with respect to a red, green or blue frequency and a polarization of light to filter by varying a geometry of its respective nanoholes,
• wherein the geometry of the nanoholes in a unit cell is selected in dependence on the light wavelength to be filtered by the respective unit cell,
• wherein each nanohole in the unit cell has its elliptical major and minor axes oriented in parallel to the respective elliptical major and minor axes of the other nanoholes in the unit cell, the orientation of the major and minor axes of the unit cell being selected in dependence on the polarization of light to be filtered by the unit cell whereby each pixel of the filter simultaneously filters a selected red, green or blue light wavelength and a polarization prior to the light reaching the array of pixels of the imaging sensor.