Research Projects

Quantum emission from low-dimensional solid-state systems plays a pivotal role in next-generation quantum technologies including quantum information, computation, metrology and secure communication. Among various solid-state emitter platforms, those operate at telecom wavelengths (~1550 nm) are particularly promising, as they align with existing fiber-optic infrastructure and offer low transmission losses over long distances. A major challenge in quantum photonics is that, although semiconductor quantum dots (QDs) can emit photons deterministically, their photon extraction efficiency at telecom wavelengths remains low, limiting practical applications. To overcome this limitation, the project aims to develop a source based on InAs/InP QDs integrated with circular Bragg grating (CBG) nanophotonic structures. The objective of this research is to engineer single-photon emitter at telecom wavelengths by epitaxially grown InAs/InP QDs with the light extraction enhancement offered by CBG structures. The project will address both the fundamental challenge of photon extraction efficiency and the applied goal of integrating the emitter into quantum key distribution (QKD) protocols, such as BB84. The project will be executed through the following main experimental stages: 1. Controlled growth of InAs/InP quantum dots emitting at 1.55 μm using epitaxial techniques. 2. Simulation and nanofabrication of circular Bragg grating structures to enhance photon extraction and emission directionality. 3. Optical characterization of the integrated QD-CBG system to evaluate single-photon purity (via second-order autocorrelation, brightness, and indistinguishability. 4. Implementation of a proof-of-concept QKD setup, incorporating the developed source to evaluate key rates and system stability under realistic conditions. The research will lead to the realization of a high-performance single-photon source compatible with existing telecom infrastructure. While QKD is one potential application, the broader impact includes advances in photonic integration, quantum networks, and fundamental studies of light–matter interaction in nanostructured media. The project combines materials growth, nanofabrication, and quantum optics, offering both scientific insights and practical value for quantum technologies.