Novel quantum-light sources

The Focus Group „Novel quantum-light sources“ involves Hans Fischer Fellow Prof. Elena del Valle (Universidad Autónoma de Madrid) and her hosts Prof. Gerhard Kramer (TUM Department of Electrical and Computer Engineering) and Prof. Kai Müller (TUM Department of Electrical and Computer Engineering).

Since the invention of the laser, classical photonics has developed into one of our most reliable, efficient and powerful technologies. Consequently, also in quantum technologies, photonics is expected to play a leading role. Currently, the bulk of the effort in quantum photonic science and technology focuses on quantum communication and is based on the development of ideal single-photon sources (SPS) as the key components. Here, sources based on semiconductor nanostructures, such as semiconductor quantum dots (QDs), offer the most desirable properties: on-demand operation, high brightness, high purity and high generation rates. However, most real-world applications will need multi-photon states of light, for example to provide redundancy against photon loss. Moreover, having efficient, controlled and pure multiphoton sources will open new perspectives beyond quantum communication, for example in photonic quantum computation, quantum sensing and metrology. The major technological goal of this focus group is to develop the multiphoton sources of tomorrow, based not on SPS (for instance through multiplexing) but instead on the direct and explicit generation of strongly-correlated non-Gaussian states of light. This is enabled by our theoretical concepts designed over the years in the realm of i) time and frequency-resolved N-photon correlations and ii) homodyning of quantum fields (making them interfere with laser light).