Photon-counting Properties of SAPHIRA APD Arrays

We measure the ability of the Leonardo Selex Advanced Photodiode HgCdTe Infrared Array (SAPHIRA) avalanche photodiode array to perform photon counting. The current SAPHIRA arrays achieve >90% single-photon efficiency (independent of quantum efficiency expected to be also >90%) and a time resolution of 125 mu s with a dark current of 21e(-)s(-1) pix(-1). Our characterization of several iterations of the SAPHIRA detector over the past 3 years of its development have also revealed a broader pulse height distribution than was originally expected.