Feasibility study for a CMOS integrated Optical Receiver for FLIM

A feasibility study for a CMOS integrated Optical Receiver for the ap- plication `FLIM' is performed. FLIM stands for Fluorescence Lifetime Imaging Microscopy and is a technique that produces an image of a bi- ological cell or tissue. Each pixel of the produced image is based on the exponential decay rate of the uorescence of a molecule; uorescence is the emission of light by a molecule that has absorbed light. The expo- nential decay rate of uorescence is unique for each molecule. The receiver, which performs a measurement for one pixel, should be able to process the very low power optical signal to a digital value that cor- responds to a unique molecule. The aim is to produce a high resolution image for Cell imaging, for which a high resolution matrix (both spatial and in time accuracy) of receivers is required. The main challenge is to design a very low noise and low area consuming receiver. Several methods in respectively time- and frequency-domain are analyzed and compared. Two methods are worked out in detail and are optimized at circuit and system level, leading to an estimate of a feasible resolution as function of the given optical input power density.