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1. Neutral Atoms for Quantum Technologies Group
Group members: Vandna Gokhroo, Ratnesh Kumar Gupta, Kristoffer Karlsson, Thomas Nieddu, Tridib Ray, Krishnapriya Subramonian Rajasree
Ultrathin (or nano) optical fibres (Fig. 1) provide a unique and non-destructive technique to probe and manipulate laser-cooled atoms and have exciting prospects in the development of hybrid quantum systems. In this subgroup we have several projects: (i) multiphoton processes with laser-cooled Rb atoms mediated via the nanofibre. The ultrahigh intensities achievable in the evanescent field allow us to explore regimes that would be very difficult to access in free space experiments, (ii) interactions between the atoms and higher order optical fibre modes for studies in quadrupole transitions and orbital angular momentum transfer, (iii) formation and manipulation of Rydberg atoms at sub-wavelength distances from the dielectric surface of an optical nanofibre for the study of atom-surface and atom-atom van der Waal's interactions, (iv) enhancement of light-matter interactions by using a nanofibre-based cavity, and (v) Purcell-enhanced single photon emission from single quantum dots (artificial atoms) coupled to a structured optical nanofibre. We predict enhancement of the coupling from the quantum dots into tailored optical nanofibres.
Fig. 1: Schematic of an ultrathin optical fibre.
2. NanoBioOptics Group
3. Optical Cavities and Sensing Group
Group Members: Jean-Baptiste Ceppe, Sho Kasumie, Fuchuan Lei, Maki Maeda, Priscila Romagnoli, Jonathan Ward
This subgroup is interested in spherical resonators, i.e. whispering gallery resonators, for applications into sensing, cavity QED, optomechanics and photonics, and other novel cavities. Recent work has focussed on (i) developing a resonator-based optical frequency comb in the visble spectral region using a microbuble resonator, (ii) nanoparticle trapping inside hollow resonators to understand the particle dynamics, (iii) laser suppresion in microcavity resonators. In the future, we plan to expand our knowledge of visible frequency combs to push the boundaries of this nonlinear effect in microresonators. We are also continuously working towards developing novel techniques and cavity geometries to try to resolve the many technical issues that inhibit the real world applications using Whispering Gallery Resonators.