Princeton Lightwave Inc. has released the PGA-600, a single-photon-counting benchtop receiver for wavelengths from 1 to 1.5 μm, suitable for quantum optics. The device integrates an InGaAs single-photon avalanche photodiode that is designed to provide a minimum detection efficiency of 25% and a dark count rate of 2 × 10–5 per trigger when operated with a 1-ns gate and 20% detection efficiency. The 19 × 17 × 7-in. instrument operates from either the internal frequency generator or an external trigger at rates up to 20 MHz. The front panel displays the number of photons counted and the number of trigger pulses in a user-defined interval, as well as diagnostic information. Operating parameters and values also can be accessed via the RS-232 interface.