Nanofabricated optical and detector elements for light-field camera sensors

Light-field cameras capture the intensity, position, and angular information of light from a scene, enabling after-the-fact focusing and 3D rendering from a single exposure. The sensitivity, pixel density, and directional resolution of light-field sensors could be increased by taking advantage of the unique photonic effects present in nanoscale and microscale structures. We demonstrate that semiconductor nanoshell whispering gallery resonators are a versatile platform for dense, ultra-thin photosite arrays. We show experimentally that an array of nanocrystalline silicon shells only 50 nm thick is as absorptive as a micron-thick planar film. We further show that we can tune the separation and size of the nanoshells by etching the underlying nanosphere template and that we can readily transfer the array onto a flexible substrate. Next, we describe the phenomenon of photonic nanojets emanating from small dielectric microlenses and microlens arrays. We devise a sensor architecture that uses the super-resolution foci formed by these nanojets to separate light into different nanoshell photosites depending on the angle of incidence. The proximity of the microlenses to the photosites corresponds to a small effective f-number, which enables main camera optics with very large apertures for light collection. In optical simulations, we demonstrate directional resolution in the integrated light-field sensor at acceptance angles of up to 35 degrees from normal incidence.