A number of quantum-based methods for computing and cryptography rely on the control and measurement of single photons. In current research applications, the focus is on characterizing the fundamental quantum nature of single photon sources and absolute counting accuracy is not important. This changes when these applications cross the threshold to commercial applications. In this case, the counting efficiency of single photon detectors becomes an important performance metric.

Within this RK contract, we will develop light sources for calibration of single photon detectors. These will be based on attenuated lasers with controlled output in the low femtowatt power regime (<10.000 photons/s). The power will be made traceable to the primary reference for optical power to ensure accurate calibration.

Single photon detector is also relevant for applications where small light signals have to be measured accurately i.e. in astronomy or biological analysis. This project will also address the need for calibration in these areas.