Carl-Zeiss-Stiftung Center for Quantum Photonics

Currently open call for four new Junior Research Group leader! In Jena, the new group will focus on Experimental Photonic Quantum Technologies.

Detailed information on the application procedure is given here. External link

The application deadline is June 30, 2023.

Doctoral students in the nano and quantum optics labs Image: MPSP

Heidemarie Schmidt (Jena), Marc Scheffler (Stuttgart), Martin Dressel (Stuttgart), Ciprian Padurariu (Ulm)

Abstract: Ultrafast superconducting single-photon nanowire detectors (SNSPDs) are versatile detectors with possible applications in quantum sensing, imaging, and information processing, e.g. in the telecom wavelength near 1550 nm in the infrared (IR). Unfortunately, SNSPDs are substantially less efficient in the IR than for visible and higher energy photons. In the project “Infrared single-photon detection via superconducting nanowires tailored by disorder, temperature, and magnetic field” groups from ACP Jena (SNSPD fabrication, transport properties), IQST Stuttgart (dynamics of superconductors), and IQST Ulm (microscopic model) will develop novel design rules and operation to enhance the IR sensitivity of SNSPDs. The research question at the heart of the project is: which new phenomena occur in the interplay of single photon absorption and vortex dynamics in a SNSPD with disorder if an external magnetic field is applied?

Illustration of the superconducting nanowire showing the vortex-lattice interacting with the vortex-antivortex pair generated by an incident photon. Image: Research Group of Prof. Heidemarie Schmidt.

Frank Setzpfandt (Jena), Tilman Pfau (Stuttgart), Joachim Ankerhold (Ulm)

Abstract: To date, many different technologies and solid-state material platforms for integrated optics have been evaluated for large-scale implementation of optical quantum information processing (QIP). However, all such platforms suffer from the same fundamental shortcoming, namely that single photons hardly interact with each other, and that very strong optical nonlinearities are required to induce all-optical interactions. The nonlinearity in solid-state materials is too weak for this purpose, and even the best state-of-the-art nanostructured nonlinear resonators can barely approach this regime. This is the main reason for the lack of on-demand and reproducible sources of single photons and scalable non-Gaussian states of light based on all-optical approaches, where such sources are highly desired for discrete variable and continuous variable QIP. The goal of this project is to create a hybrid platform for integrated optical QIP that can overcome this fundamental shortcoming. This will be done by utilizing the unique properties of atomic vapors of rubidium, in particular their few-photon nonlinearity, integrated with the nanostructured optical platform of lithium niobate on insulator (LNOI), which is one of the most promising candidates for the realization of integrated optical QIP systems. To create this hybrid platform and to explore its unique capabilities, we will combine the complementary expertise of the universities of Jena (expertise on nanostructured LNOI for integrated optics), Ulm (expertise on description of complex quantum systems), and Stuttgart (expertise on atomic vapors for quantum optics). We will establish the practical and technological foundation for the creation of this new hybrid platform and perform preliminary experimental demonstrations showing that this is a functional quantum optical system. In addition, we want to theoretically study the new possibilities for QIP that can result from such a hybrid platform.

Schematic of atomic vapors surrounding a nanostructured integrated waveguide. Image: Robert Löw, University of Stuttgart.