Development of an ultrafast single photon counting imager for single molecule imaging.

We have begun developing an innovative ultra-fast single-photon counting imager which comprises a mega-pixel CMOS array and a newly-designed Image Intensifier. It is expected to have single photon sensitivity with 100 psec time resolution, operational at a total counting rate exceeding 1MHz. The readout is based on dead-time-free flash ADC, running at 1-2GS/s, followed by a FPGA for real-time parallel data processing. Such a device has not been realized before and is expected to revolutionize time-resolved fluorescence imaging and spectroscopy from a single-molecule to whole animal level. To evaluate the design principle, an Image Intensifier with a GaAsP photocathode (>40% quantum efficiency at 400-600 nm) followed by double MCP was evaluated together with an existing CMOS camera. In our future design, the image from CMOS Camera will be combined with the MCP output, followed by a set of FPGA and CPU for real time data processing. This stream line method will allow ultra fast single-photon counting with 100 psec time resolution and 20 µm position resolution (1M pixel imaging). In this paper, we present the design principle and preliminary results on its performance. Our future plan and the design goals are also described.