Modern single-photon counters: Time- and location-resolved quantum detection with SPAD arrays
The quantum nature of light can be described in simplified terms by accepting the concept of light particles (photons) in addition to the image of light as an electromagnetic wave. Both descriptions are physically valid because experiments can be carried out for both waves and particles. Photon counters based on the avalanche effect, i.e., avalanche photodiodes or APDs, have proven particularly helpful in this regard. These can detect the arrival of a photon with very high temporal precision. Many photon properties, like antibunching in single-photon emitters or entanglement, can only be theoretically explained by using non-classical physics. Aforementioned photon counters are perfectly suited for the detection of these properties, thanks to their excellent time resolution. Avalanche photodiodes designed as multi-channel detectors, on the other hand, are less common.
With the SPAD arrays (single-photon avalanche diodes) from PI Imaging, Quantum Design now offers true multi-channel photon counters. These enable spatial information to be obtained in addition to the time of arrival. The SPAD cameras are available in various designs, as a 512 x 512 pixel array, with 1024 x 1024 pixels and an optional RGB color mask, or in a hexagonal circular arrangement with 23 or 93 diodes. Optimization using a microlens array improves the quantum efficiency of the sensor. This expands our extensive range of photon-counting cameras in the visible spectral range.
In addition, we also offer a linear array of diodes. In combination with a spectrograph, this can be used to perform high-resolution spectroscopy.
