Spectral routers for snapshot multispectral imaging

Stanford researchers working as part of the E. L. Ginzton Laboratory, an interdisclplinary research lab for applied physics, have developed a new device, called a spectral router, which can separate light into spectral components without loss of photons in a (sub)wavelength size footprint. This spectral router enables single-chip snapshot spectral imaging sensors and systems that are highly (up to ~100%) photon efficient to provide spectral information without sacrificing spatial information. A spectral router in a single-chip snapshot imaging system with N spectral channels can improve photon efficiency N-fold, in a much smaller footprint, compared to a conventional multispectral filter array. While spectral routers benefit all spectral imaging applications, this extremely compact and photon efficient solution can also further increase multispectral imaging use cases by enabling photon-efficient, high-spatial resolution systems on highly portable platforms (e.g., smart phones, tablets).

Figure Description:(a) Conventional on-chip solution for single-chip spectral imaging systems based on spectral filter array with photon-inefficient spectral filters which are larger than the wavelength and thus limit the spatial resolution of the captured image, (b) Spectral router providing highly efficient routing of spectral components in a (sub)wavelength footprint without sacrificing spatial resolution in the image, (c) Example spectral router with 6 spectral channels, in a 2 by 3 channel layout, in the visible wavelength range. The optical efficiency of the router can be ideal (~100%) for the 6 channels with negligible (~0%) crosstalk between channels. For comparison, the gray line in the graph shows the maximum theoretical efficiency (=1/6) of a spectral filter array.

Stage of Development