Back-illuminated pulse-frequency-modulated photosensor using silicon-on-sapphire technology developed for use as epi-retinal prosthesis device

An intra-ocular epi-retinal prosthesis device using a back-illuminated photosensor is proposed and demonstrated for the first time. The photosensor, based on a pulse frequency modulation, is fabricated on a transparent sapphire substrate to detect the backside incident light. Experimental results show that the device is sensitive over a dynamic range of incident light of 30 dB.