Thorlabs - Model SPCM20A(/M) and SPCM50A(/M) -Single Photon Detectors
Thorlabs` Single Photon Detectors, which use a silicon avalanche photodiode to detect single photons, are sensitive to photons emitted in the 350 to 900 nm range, with the maximum sensitivity around 500 nm (see the graph to the right). Incoming photons are counted by an internal 31-bit counter. In addition, an output SMA connection offers a signal that can be viewed on an oscilloscope or connected to an external counter. Please see the Tutorial tab for details about the functionality of this photon counter.
An integrated Peltier element stabilizes the diode`s temperature below the ambient temperature to reduce the dark count rate. The two available models, SPCM20A and SPCM50A, have low typical dark count rates of 25 and 150 counts per second, respectively, which allows them to detect power levels down to 0.14 fW.
The active quenching circuit integrated into the diode of the single photon detector enables high count rates. Its high speed allows users to count a photon every 35 - 45 ns, depending on the model chosen. The SPCM20A provides an active area of Ø20 µm while the SPCM50A offers Ø50 µm.
Software
The Single Photon Counter Module includes a software package with GUI for out-of-the-box operation. The following operating modes can be set by the software:
- Manual Mode for manual operation
- Free Running Timer Counter for counting incident photons for a certain number of "Time Bin Lengths"
- Externally Triggered Timer Counter for triggering the timer start for counting incident photons for a certain time period
- Externally Triggered Counter for starting and stopping the counter by an external trigger
- External Gating for activating the counter and the APD externally
For more details about the software and its operation modes, please see the Software tab.
- Low Dark Counts
- SPCM20A(/M): 25 Hz (Typical)
- SPCM50A(/M): 150 Hz (Typical)
- Two Detector Sizes
- SPCM20A(/M): Ø20 µm Active Area
- SPCM50A(/M): Ø50 µm Active Area
- Active Quenching
- Temperature Stabilized
- USB Interface
- Pulse Output
- TTL Gating/Trigger Input
- Compact Size: 76.5 mm x 85 mm x 36.2 mm
- Spectroscopy with Single Molecules
- Spectro-Photometrical Measurements
- Flow Cytometry
- Photon Correlation Spectroscopy
- LIDAR
