SPID: Single Photon Imaging device L. Neri 1,2 , S.Tudisco 1 , L. Lanzanò 1,2 , F. Musumeci 1,2 , S. Privitera 1,2 , A. Scordino 1,2 , G. Condorelli 3 , G. Fallica 3 , M. Mazzillo 3 , D. Sanfilippo 3 , G. Valvo 3 1 INFN-Laboratori Nazionali del Sud, via Santa Sofia 65, 95125 Catania (Italy) 2 DMFCI-Dip. Met. Chim. Fis. Ing. & Dip. di Fisica ed Astronomia, Università di Catania 3 R&D, ST-Microelectronics, Stradale Primosole 50, 95100 Catania (Italy) ABSTRACT Today, single photon imaging represents one of the most challenging goals in the field of photonics. Many areas are involved: nuclear and particle physics, astronomy, and, in the biophysics field, the newest technique to investigate the state of several biological systems by detecting the ultra-weak luminescence emitted from the excited sample under study. Aim of the work is the realization of a single photon imaging device able to identify the position and the arrival time of the impinging photons from ultra low intensity sources. The main features of a 2-D array of Single Photon Avalanche Diodes, manufactured by ST-Microelectronics, are shown. Keywords: SPAD, time resolved, single photon, image, avalanche diode, avalanche quenching 1. INTRODUCTION The observation of a source of photons is one of the most common research techniques. Among all the techniques that the newest technology allows to perform, it is less intrusive and never destructive. It is used to study physical, astrophysical, biological phenomena; it is also very important in medical and industrial applications [1-2]. For these reasons the scientific research works to obtain the greatest number of information from the optical analysis. The spatial description of the photons source is one of the most useful information. The single photon sensitivity allows to obtain information from very low intensity radiation, extending the range of investigation. Time resolved analysis gives information about time decay and correlations between different photons sources. The goal of our research is the realization of Time Resolved Single Photon Imaging, which simultaneously includes time resolution, single photon sensitivity, and spatial description of the source: the result is a new technique that gives much information than the single task separately. The new developed technology is based on the use of Single Photon Avalanche Diode (SPAD) with the aim to overcome the limit of the CCD technology. Even if there are many type of high tech CCD, the incoming SPAD technology has shown better performance since the starting application. The real time response from single photon and single pixel, ensure greater sensibility and excellent timing, until to tens picoseconds [3]. Room temperature operability, good quantum efficiency in the visible region and in the near infrared [4], low power consumption, and ease application design are the strengths of this new technology [5]. 2. TIME RESOLVED SINGLE PHOTON IMAGING CANDIDATE The electronic device core of the sensor that we are developing is the Single Photon Avalanche Diode, used in Geiger mode. This is a diode working in inverse bias voltage, 10-20% over the breakdown voltage. When a photon is absorbed into the depletion region the diode moves from a non conductive state to a conduction state. The photon generates a electron-hole pair and if the electric field in the material is great enough to accelerate free charge to the point that, when they strike atoms in the material, they can knock other electrons free: the number of free electrons increase rapidly and we obtain an avalanche macroscopic current that is time correlated with the photon. High Energy, Optical, and Infrared Detectors for Astronomy III, edited by David A. Dorn, Andrew D. Holland, Proc. of SPIE Vol. 7021, 702129, (2008) · 0277-786X/08/$18 · doi: 10.1117/12.791013 Proc. of SPIE Vol. 7021 702129-1 2008 SPIE Digital Library -- Subscriber Archive Copy