PhD position on quantum photonic circuits

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label Burse autorenew 2025-09-29, 17:01 history_edu Maria Dumitru
Quantum information processing enables new paradigms for computing and communication, leading for example to new algorithms for solving problems which are computationally difficult (quantum computing) and to physically-secure quantum cryptography. Photons are one of the preferred physical implementations of quantum bits, due to the long propagation distance, and several ideas and first demonstrations of quantum gates operating with photons are being investigated.

However, any practical implementation of a small quantum circuit operating with photons faces the critical requirement of scalability: Present table-top experiments using bulky optical components or fibers cannot be practically scaled beyond few qubits due to the large number of components needed and to the high coupling loss. Our group is pursuing an alternative and potentially revolutionary approach to quantum networks, which is based on integrating single-photon components (sources, detectors, gates) on a single semiconductor chip.

These solid-state optical circuits operating at the single-photon level are in principle scalable to hundreds and thousands of devices, opening the way to a small-scale quantum processor. We have already demonstrated some of the key building blocks (sources [1], detectors [2]) of this integrated quantum technology, and we are planning to start investigating small circuits operating at the level of two or few photons.

Project description



The selected candidate will perform fundamental research at the interface between nanophotonics and quantum optics. He/she will conceive and fabricate solid-state nanophotonic devices and small optical circuits operating at the single-photon level, using advanced nanotechnology tools, and investigate the quantum optical photon-photon interactions in view of their application to quantum information protocols.

Some examples include quantum interference of two or more single photons on a chip, the investigation of the stimulated emission process at the single-photon level, and the application of single-photon nonlinearities to quantum gates. The project will be supervised by Prof. A. Fiore.

References:

[1] Hoang et al., Optics Express 20, 21758 (2012)

[2] Sprengers et al., Appl. Phys. Lett. 99, 181110 (2011)