Dr Tintu Kuriakose

Abstract:

<jats:p>Semiconductor photonic nanowires are critical components for nanoscale light manipulation in integrated photonic and electronic devices. Optimizing their optical performance requires enhanced photon conversion efficiency, for which a promising solution is to combine semiconductors with noble metals, using the surface plasmon resonance of noble metals to enhance the photon absorption efficiency. Here, we report plasmon-enhanced light emission in a hybrid nanowire device composed of perovskite semiconductor nanowires and silver nanoparticles formed using superfluid helium droplets. A cesium lead halide perovskite-based four-layer structure (CsPbBr3/PMMA/Ag/Si) effectively reduces the metal’s plasmonic losses while ensuring efficient surface plasmon–photon coupling at moderate power. Microphotoluminescence and time-resolved spectroscopy techniques are used to investigate the optical properties and emission dynamics of carriers and excitons within the hybrid device. Our results demonstrate an intensity enhancement factor of 29 compared with pure semiconductor structures at 4 K, along with enhanced carrier recombination dynamics due to plasmonic interactions between silver nanoparticles and perovskite nanowires. This work advances existing approaches for exciting photonic nanowires at low photon densities, with potential applications in optimizing single-photon excitations and emissions for quantum information processing.</jats:p>

Abstract:

Photonic platforms are an excellent setting for quantum technologies as weak photon–environment coupling ensures long coherence times. The second key ingredient for quantum photonics is interactions between photons, which can be provided by optical nonlinearities in the form of cross-phase modulation. This approach underpins many proposed applications in quantum optics^{1,2,3,4,5,6,7} and information processing⁸, but achieving its potential requires strong single-photon-level nonlinear phase shifts as well as scalable nonlinear elements. In this work we show that the required nonlinearity can be provided by exciton–polaritons in micropillars with embedded quantum wells. These combine the strong interactions of excitons^9,10 with the scalability of micrometre-sized emitters¹¹. We observe cross-phase modulation of up to 3 ± 1 mrad per polariton using laser beams attenuated to below the average intensity of a single photon. With our work serving as a stepping stone, we lay down a route for quantum information processing in polaritonic lattices.

Abstract:

Controlling low power light beam self-confinement with ultrafast response time opens up opportunities for the development of signal processing in microdevices. The combination of a highly nonlinear medium with the tight confinement of plasmonic waves offers a viable but challenging configuration to reach this goal. In the present work, a beam propagating in a plasmonic structure that undergoes a strongly enhanced self-focusing effect is reported for the first time. The structure consists of a chalcogenide-based four-layer planar geometry engineered to limit plasmon propagation losses while exhibiting efficient Kerr self-focusing at moderate power. As expected from theory, only TM-polarized waves exhibit such a behavior. Different experimental arrangements are tested at telecom wavelengths and compared with simulations obtained from a dedicated model. The observed efficient beam reshaping takes place over a distance as low as 100 μm, which unlocks new perspectives for the development of integrated photonic devices.

Abstract:

We report the experimental observation of plasmon-soliton waves. The demonstration is performed in a chalcogenide-based four-layer planar geometry. It reveals a plasmon-enhanced Kerr selffocusing undergone by a TM polarized beam propagating inside the structure.