Quantum Light Detection

Avalanche Photodiodes (APDs) are a semiconductor technology that converts a single photon into a single electron, which starts an amplification ‘avalanche’ creating thousands more electrons, and a measurable electrical current. To detect the smallest avalanches, and allow superfast operation, our research has led to the Self-Differencing APD, which compares electrical signals with, and without a photon, isolating the output due to light detection. This allows us to detect up to 1 billion individual photons per second.

Single photon avalanche diodes (SPADs) are a versatile technology which can be used in a wide range of quantum information applications including QKD and quantum imaging.  We can optimise the detector to the application by tuning properties such as the single photon detection efficiency and pixel number.

The newly developed quantum detectors offer extraordinary sensitivity combined with high timing resolution. By detecting weakly reflected laser pulses from distant objects, those features can be exploited to create quantum enhanced imaging systems that can outperform the 3D cameras or LiDAR systems available today. Such systems can ensure the safety of driver assisted and autonomous vehicles under challenging weather conditions.