The Light-Matter Interactions for Quantum Technologies (LMI-QT) Unit, led by Prof. Síle Nic Chormaic, conducts research in quantum, atomic, and optical physics.  The unit is organised into three subgroups: Neutral Atoms for Quantum Technologies, NanoBioOptics, and Optical Cavities & Sensing.  To learn more about our research themes, please visit our research and publications pages.   If you are inspired by the beauty of classical or quantum light and the profound role it plays in the world, you will find a stimulating and welcoming research environment here. 

We explore light as a tool in classical physics, such as when optical forces are used to push or pull individual particles (think of where a comet's tail comes from!), for probing the dynamics of colloidal particles (such as cells, bacteria, or model micro or nanospheres), or even light's ability to detect very small numbers of particles. 

Byeond the classical regime, we also consider light's role in quantum physics.  Photons can be used to slow neutral atoms through laser-cooling, and, when combined with magnetic fields in a magneto-optical trap (MOT), to confine and cool atoms to temperatures of about 100 microKelvin.  These techniques underpin the development of next-generation quantum technologies based on neutral ground state and highly excited Rydberg atoms.    

We study the interaction between light and matter across a range of platforms, including cold atomic systems, whispering gallery mode microresonators, and biologically relevant samples.  Our goal is to deepen our understanding of the underlying processes involved and to manipulate or trap micron and nanoscaled particles using tailored light fields.  A unifying tool across our research is the use of optical nanofibres, which serve as a highly efficient interface between light and the sample under study.  

Researchers in our unit develop a braod and transferable skill set spanning optics, quantum technologies, atomic physics, numerical simulations, photonics, electronics, vacuum, cryogenics, nanofabrication, instrumentation, and programming.  Much of our work is interdisciplinary bridging physics with chemistry, material science, life science, and engineering.  

Although most of our research is fundamentally drive, it relies on technical expertise that is directly relevent to industry, particularly QTech, precision optics, nanofabrication, automation, system modelling, and control engineering.   

Our facilities include three magneto-optical traps for rubidium (two dedicated to Rydberg atom research), four optical nanofibre pulling rigs, multiple microscoyp systems, muliple optical tweezers.  We operate a broad suite of lasers, from visible to near IR, diole lasers to Ti:Saph setups, optical spectrum analysers, vector network analyser, high speed oscilloscopes, wavemeters. Additional capabilities include access to a fully equipped clean room facility, SEMs, and FIBs, 2-photon printing, and so on.

Students interested in studying for a PhD with us should apply through the OIST Graduate University PhD Programme at https://groups.oist.jp/grad or contact us for informal discussions about the entry requirements.    We seek students with a strong combination of experimental and analytical skills, with emphasis in classical and quantum optics.    We can only accept students who officially apply through the Graduate School programme, which provides a full scholarship for 5 years and conference travel costs. Previous students are employed in QTech startups, large-scale research facilities, optics-related industries, as software engineers, at universities, in airlines, or are involved in scientific policy. 

If you are a student and wish to spend a research period of up to 6 months with our group, we'd be happy to consider your application.  OIST also offers a dedicated research intern programme for BSc or MSc students from Japan or Overseas -  details are available at https://admissions.oist.jp/oist-research-internship-program-description.   Please email Prof. Nic Chormaic to discuss opportunities.

 

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OIST Center for Quantum Technologies

This unit is a member of the OIST Center for Quantum Technologies (OCQT)

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Unit Posts

21 February 2026: Latest Publication - Nano Lett.

Topological quasiparticles such as skyrmions have been observed in the spin angular momentum density of propagating surface waves such as surface plasmon polaritons, but their spatial resolution remains diffraction limited. Here, we demonstrate the creation of few-nanometer-scale transverse spin textures with nontrivial topology near nanogaps formed by localized, oscillating charges. By tuning the phase delay between neighboring charges, a localized momentum flow emerges, encircled by a transverse spin vortex. The vortex orientation is dictated by left-handed spin-momentum locking, intrinsically linked to the transport of electric field saddle-point singularities across the nanogap. Increasing the number of oscillating charges leads to complex nanoscale spin angular momentum textures, including toroidal vortices and skyrmions. These results show that localized surface plasmon resonances in metallic multimer nanostructures enable the generation of deep-subwavelength electric field spin textures. This approach opens new pathways for controlling the spin properties of light at the nanoscale, far beyond the diffraction limit.

15 February 2026: Latest Publication - Phys. Rev. A

We present a magnetic trapping scheme for cold Rb-87 atoms based on light-induced fictitious magnetic fields generated by the evanescent field of an optical nanofiber (ONF) integrated with optical tweezers. We calculate and compare the trapping potentials for both Gaussian and Laguerre-Gaussian modes of the tweezer beam, combined with a quasilinearly polarized ONF-guided field. Based on the optical powers in the tweezer and ONF modes, we analyze the trap depths and the positions of the potential minima from the nanofiber surface. We show that, by varying the optical powers in the two fields, the trap position can be tuned over several hundred nanometers while simultaneously influencing the trap depth and trap frequencies. Such control over the atom-surface position is essential for studying distance-dependent effects on atoms trapped near a dielectric surface and optimizing atom-photon interfaces for quantum technology applications.

24 January 2026: Latest Publication - Quantum Sci. Tech.

A promising platform for quantum information research relies on cavity coupled atomic spin-waves, enabling efficient operations such as quantum memories, quantum light generation and entanglement distribution. In this work, we study the strong coupling between non-classical collective spin excitations generated by Raman scattering in a cold Rb atomic ensemble, and a single cavity mode. We report on an intracavity spin wave to single photon conversion efficiency in the quantum domain, as evidenced by a violation of the Cauchy–Schwarz inequality. Our work establishes a relationship between the retrieval of an atomic spin wave in the non-classical regime and the vacuum Rabi splitting. We show that this relationship emerges within the efficiency spectrum, and we finally provide the optimal operational conditions to achieve the maximum intrinsic retrieval efficiency. Our data is well reproduced by simulations based on optical Bloch equations. This work deepens the understanding of cavity-enhanced spin wave readout and its potential applications.

24 January 2026: Latest Publication - Adv. Photonics Nexus

Chaotic microcavities play a crucial role in several research areas, including the study of unidirectional microlasers, nonlinear optics, sensing, quantum chaos, and non-Hermitian physics. To date, most theoretical and experimental explorations have focused on two-dimensional (2D) chaotic dielectric microcavities, but there have been minimal studies on three-dimensional (3D) ones because precise geometrical information of a 3D microcavity can be difficult to obtain. Here, we image 3D microcavities with submicron resolution using X-ray microcomputed tomography (μCT), enabling nondestructive imaging that preserves the sample for subsequent use. By analyzing the ray dynamics of a typical deformed microsphere, we demonstrate that a sufficient deformation along all three dimensions can lead to chaotic ray trajectories over extended time scales. Notably, using the X-ray μCT reconstruction results, the phase space chaotic ray dynamics of a deformed microsphere are accurately established. X-ray μCT could become a unique platform for the characterization of such deformed 3D microcavities by providing a precise means for determining the degree of deformation necessary for potential applications in ray chaos and quantum chaos.

01 November 2025 - Publication in Adv. Opt. Mat.

Precise positioning of quantum emitters is essential for next-generation photonic technologies, yet conventional free-space optical trapping methods require high laser powers that damage sensitive nanoparticles through heating. Here, ultralow-power trapping of biocompatible molecular graphene quantum dots (GQDs) is demonstrated using metamaterial plasmonic tweezers, achieving record-high normalized trap stiffness values at low intensities. Custom 19-nm molecular GQDs containing twisted double[7]carbohelicene (D7H) molecular cores are synthesized and their trapping dynamics are systematically investigated across dual hotspot types in the metamaterial array. The results establish safe operating regimes for heat-sensitive quantum emitters and reveal the fundamental interplay between optical and thermal forces in plasmonic trapping systems. This platform enables efficient nanopositioning of quantum emitters in ordered arrays while maintaining biocompatibility and photostability, opening pathways toward scalable single-photon source architectures and bioimaging applications.
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