Tunable Plasmonic Filters Enable Time-Sequential Color Imaging

ACS Photonics paper "Tunable Multispectral Color Sensor with Plasmonic Reflector" by Vladislav Jovanov, Helmut Stiebig, and Dietmar Knipp from Jacobs University Bremen and Institute of Photovoltaics Jülich, Germany proposes plasmonic reflectors for color imaging:

"Vertically integrated color sensors with plasmonic reflectors are realized. The complete color information is detected at each color pixel of the sensor array without using optical filters. The spectral responsivity of the sensor is tuned by the applied electric bias and the design of the plasmonic reflector. By introducing an interlayer between the lossy metal back reflector and the sensor, the reflectivity can be modified over a wide spectral range. The detection principle is demonstrated for a silicon thin film detector prepared on a textured silver back reflector. The sensor can be used for RGB color detection replacing conventional color sensors with optical filters. Combining detectors with different spectral reflectivity of the back reflector allows for the realization of multispectral color sensors covering the visible and the near-infrared spectral range.

To our knowledge for the first time a sensor is presented that combines a spatial color multiplexing scheme (side-by-side arrangement of the individual color channels) used by conventional color sensors with the time multiplexing scheme (sequential read-out of colors) of a vertically integrated sensor."