Cavity-enhanced multispectral photodetector using phase-tuned propagation: theory and design.

We propose and theoretically analyze what we believe to be a novel design of cavity-enhanced photodetectors capable of sensing multiple wavelengths simultaneously in a single pixel. The design is based on phase-tuned propagation of resonant modes in cascaded planar resonant cavities. We show that this concept can be generalized to detect multiple wavelength combinations covering the entire near to far infrared spectrum. Besides its multispectral detection capability, the design also features minimal spectral cross talk and significantly suppressed noise. The intrinsic design versatility and scalability, as well as process compatibility with planar microfabrication, suggest the design's wide application potential for telecommunications, infrared imaging, and biochemical sensing.