Plasmonic Color Filters Coupled with CMOS Photodetectors Integrated Within the Device

Modern, portable electronics employ CMOS image sensor arrays, which have tiny active pixels that are well-suited to the subwavelength mode volumes of plasmonic filters. Broad transmission bandwidths (> 100 nm) are characteristic of most plasmonic filters, making them ideal for CMYK or RBG color filtering. Achieving CMOS image sensors with multi- and hyperspectral imaging capabilities would be possible with a significant reduction in the peak width of filter transmission spectra. Single transmission bands as thin as 17 nm are produced by multi-mode interference phenomena, which are induced by the design of 4-layer metal-insulator-metal-insulator-metal structures. These phenomena reduce spurious transmission characteristics. The fundamental structure of these multilayer slot-mode plasmonic filters (MSPFs) may function across a wide range of wavelengths, allowing for systematic variation of the transmission peaks over the visible and near infrared spectra. This, in turn, produces a filter that can be integrated into complementary metal-oxide semiconductors (CMOS). We provide practical prototypes of MSPF filter designs that can attain a visible bandwidth of less than 30 nm and a full width at half maximum (FWHM) of 50 nm. We also detail how to make the experimental structure approach the limitations proposed by the model.