Single Photon Counting Modules

The Excelitas family of Single-Photon Counting Modules (SPCMs) are self-contained modules that meet the low-light-level detection demands of confocal microscopy, fluorescence, luminescence, and TCSPC, particle sizing and Quantum Communications. Our SPCMs offer market-leading Photon Detection Efficiency (PDE), low after-pulsing, highest uniformity over the active area, high linear dynamic range, and low dark counts.

Interested in how Single Photon Detection has evolved over the years and into today's turn-key modules that provide simple, plug-and-run photon detection for OEMs and laboratories alike?  Read our latest white paper

Excelitas' SPCMs are available to purchase online at - buy now for quick delivery!

Additional Resources
Why should you choose Excelitas as your provider of Single Photon Counting Modules?
With more than 30 years of photon counting design and engineering expertise, Excelitas Technologies proudly delivers high-quality, high-performance Single Photon Counting Modules (SPCMs) designed for the most demanding low-light-level detection applications. We combine our technical expertise with global resources to support the needs of our customers and provide solutions that best meet your photon counting applications. As the first company to introduce SPCMs that utilize the power of silicon avalanche photodiodes (Si APDs), our commitment remains to continue delivering cutting-edge solutions as a market leader and innovator in the photonics industry.
What are the different uses of Single Photon Counting Modules?
SPCMs are specialized devices used for detecting and counting individual photons with great precision and accuracy. Excelitas utilizes Silicon APDs in manufacturing our photon modules, which are advantageous as they can help achieve maximum peak photon detection over a 180µm diameter circular active area. Temperatures typically increase during this process, so the photodiodes are temperature-controlled using a double-stage thermoelectric cooler to ensure the system’s stability and optimal signal-to-noise ratio as the temperature fluctuates. These capabilities are crucial and well-suited for a wide range of applications, including fluorescence, luminescence, confocal microscopy, time-correlated single photon counting (TCSPC), quantum communications and particle sizing.
What types of Single Photon Counting Modules do you offer?
Excelitas offers a comprehensive series of high performance SPCMs for the most demanding low-light-level detection applications including:
  • SPCM-AQ4C - four-channel photon counting modules that detect single photons between the 400 nm to 1060 nm wavelength range.
  • SPCM-AQRH - this module detects single photons of light between the 400 nm to 1064 nm wavelengths while offering superior performance parameters as compared to other solid-state or vacuum-tube-based photon counters.
  • SPCM-AQRH-TR - as part of the latest SPCM product generation, this module is specifically selected and optimized to achieve timing resolution while supporting applications in TCSPC, fluorescence lifetime measurements and fluorescence lifetime imaging microscopy (FLIM).
  • SPCM-NIR – single-photon counting photon modules that have been performance-optimized for the near-infrared (NIR) wavelength spectrum and designed to support long range light detection and ranging (LiDAR), quantum communication and microscopy applications, among others.
What are the applications of Single Photon Counting Modules?
Excelitas offers a comprehensive range of SPCMs well-suited for a wide range of cutting-edge applications, including the following:
  • Dynamic Light Scattering (DLS) Particle Sizing
  • Stimulated Emission Depletion (STED) & Multi-Photon Microscopy
  • Ultra-Sensitive Fluorescence
  • Luminescence
  • Single Molecule Detection
  • Diffused Correlation Spectroscopy (DCS)
  • Single Photon LiDAR
  • Optical Range Finding
  • Quantum Cryptography (QKD)
  • Photon Entanglement Experiments
Do you offer custom Single Photon Counting Modules?
Yes, we do. Excelitas is a product leader in the design, development and manufacturing of high-quality SPCMs designed to meet your intended applications. Our SPCM solutions follow the strictest standards to ensure their reliability and robust performance. Look through our comprehensive off-the-shelf solutions to find devices that satisfy your performance requirements. If you are unable to find solutions that match the specifications of your intended application, get in touch with us for customized solutions tailored to your specific needs. We collaborate with you through every stage of the design and development process to ensure the quality of the product without compromising cost, reliability and time-to-market. Rest assured that these products will abide by our strict quality standards.
Single Photon Counting Modules

Product List

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The SPCM-AQ4C is a four-channel photon counting module capable of detecting single photons of light over the wavelength range from 400 nm to 1060 nm. Each channel is independent from the others.
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Excelitas' newly enhanced SPCM-AQRH Single-Photon Counting Module detects single photons over the wavelength range of 400 nm to 1064 nm with performance parameters superior to other solid state or vacuum-tube based photon counters.
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The Excelitas SPCM-AQRH-WX-TR is a Single Photon Counting Module of the latest product generation, specifically selected and performance-optimized for timing resolution. This family of –TR modules is designed to support applications in time-correlated single-photon counting (TCSPC), fluorescence lifetime measurements and fluorescence lifetime imaging microscopy (FLIM).
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SPCM-NIR-wx with -FC or -BR1/2 Options


The Excelitas SPCM-NIR is a Single-Photon Counting Module specifically selected and performance-optimized for the near-infrared wavelength spectrum. This NIR spectrum enhanced device is designed to support long range LiDAR, quantum communication and microscopy, as well as many other applications.