The SPCM50A Photon Counter Module uses a silicon avalanche photodiode to detect single photons. The SPCM counter is sensitive to photons emitted in the 350 to 900 nm range with the maximum sensitivity at 500 nm. This works by converting an incoming photon into a TTL pulse in the detector, which is counted by the internal 31-bit counter. An additional USB connection offers a direct output pulse signal from the module that can be viewed on an oscilloscope or connected to an external counter.
An integrated Peltier element stabilizes the diode's temperature below the ambient temperature to reduce the dark count rate. The SPCM50A has low typical dark count rates of 150 counts per second, respectively, which allows it to detect power levels down to 0.14 fW.
The active quenching circuit integrated into the diode of the SPCM enables high count rates. The SPCM50A’s high speed allows users to count a photon every 45 ns and provides an active area of Ø50 µm. The SPCM includes a software package with GUI for out-of-the-box operation.
Detector Type: Si Avalanche Photodetector
Wavelength Range: 350 – 900 nm
Active Detector Diameter: 50 µm
Typical Max Responsivity: 35% at 500 nm
Dark Count Rate Typical: 200 Hz Max (150 Hz Typical)
Max Count Rate: 22 MHz
Dead Time: 45 ns (Typical)
Apd Gating Delay: 18 ns (Typical)
Gate/Trigger In to Pulse Out Delay: 28 ns (Typical)