Quantum technologies – currently under development – will probably play an important role in telecommunication networks in the near future. Compatibility with the conventional optical fiber network is necessary, thus the required operational wavelength of the planned quantum optical system is around 1550 nm. The semiconductor based avalanche photodiodes have high noise level and moderated sensitivity in this wavelength range, hence other detector technologies became important. One of the most promising solutions is the superconducting nanowire single photon detector (SNSPD). In these detectors a constant superconductive current flows through the cooled nanowires, setting the operation point slightly below the threshold of normal conduction. Upon the absorption of incident photons Cooper-pairs are split up, therefore the resistance of the wire is locally increased. Measuring the temporal changes of the resistance enables us to detect infrared photons.
The goal of the PhD student will be to develop a physical model that describe the coupled optical and conduction effects. New thin film structures will be proposed to increase the optical coupling of the detector. Furthermore new nanowire structures and material technologies should be developed to enhance the main parameters of the detector, like quantum efficiency, dead time, operating temperature etc. The manufacturing processes and the validation experiments of the detectors will be implemented in cooperation with the Institute of Technical Physics and Materials Science
MSc in physics, model and experiment developing skills