High Speed Room Temperature IR Camera Based on Plasmon Physics

It is desirable to make focal plane arrays (or imaging arrays) with reduced pitch; doing so enables smaller, cheaper and lighter camera systems that provide the same image resolution. Currently, the lower limit on pitch is set by electron/hole diffusion and light diffraction that results in crosstalk between neighboring pixels. Since electron hole pairs generated outside the depletion layer can be collected anywhere within 1 diffusion length scale, when the pitch is reduced below the diffusion length scale, the resultant resolution is compromised. On the other hand, if the individual detectors are made smaller than the wavelength of light, then they become nearly transparent to the light, and the quantum efficiency is compromised. In this proposal, we will implement a new photodiode architecture that was developed in the Phase I. In this photodiode, the optical energy of incident light is first compressed into a very small volume. The compressed optical energy is focused onto the depletion layer of a nanoscale photodetector, thereby preventing any electron-hole pair generation outside the depletion layer. Thus, we will circumvent the diffusion limit, and also the diffraction limit. During the Phase II project, we will implement specific designs of this architecture at LWIR wavelengths using mercury-cadmium-telluride alloys and at visible wavelengths using silicon compatible materials.