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Quantum optics and mesoscopic systems

qoms image
(left) Avoided crossings of a quantum dot molecule transitions. (middle) A typical measurement setup. (right) Bow-tie nanoantenna structures fabricated on a chemically grown gold flake.

Quantum-dot spins and quantum information

Coherence properties of electron and hole spins in semiconductor quantum dots have lead to a concerted effort in the direction of quantum information processing in recent years. Our research efforts focus on the ability to optically control and manipulate the dynamics of few spins in quantum confined systems. The physical systems will include both coupled quantum dots for spin-pair configurations and quasi-2D structures for many-body effects in the presence of weak coupling. We also focus on utilizing quantum dots for quantum metrology applications such as electric field and mechanical displacement sensing devices.

Nanoplasmonic and Cavity Quantum Electrodynamics

The formation of localised plasmon polariton modes at the interface of metals and dielectrics allows an alternative approach to solid-state-based cavity QED at sub-wavelength scale. We fabricate and study metal/dielectric nanostructures with the aim of achieving individual or ensemble strongly coupled emitter-cavity systems. Further, we work on fabrication techniques to obtain single crystal gold with atomic level smoothness, which in turn suppresses the major problem of loss in plasmonic systems.

High-Resolution Coherence Spectroscopy of Optically Active Impurities in Diamond

Colour centres in diamond provide a suitable test bed for applications of quantum information processing and ultrasensitive quantum metrology. While there are hundreds of known colour centres in diamond, only one, the nitrogen vacancy, has been studied extensively. One of our research goals is to identify alternative colour centres with superior properties for these applications. The colour centres currently under investigation are based on Cr, Ni, and Si impurities in bulk and nanocrystal diamond.