Conference Agenda

2D-Transition Metal Dichalcogenides (2D-TMDs) are promising two-dimensional semiconductors with high optical absorption coefficient in the visible range. While exfoliated TMD flakes offer superior optoelectronic performance, scalable large-area growth is essential for real-world applications [1,2]. For light conversion at extreme thicknesses, nanophotonics-based flat optics strategies are key.

We demonstrate that periodic modulation of MoS₂ on nanostructured surfaces—via laser interference lithography—can steer light using Rayleigh Anomalies, enhancing in-plane electromagnetic confinement and broadband photon absorption [3,4,5].

Addressing scalability, we also present cm²-scale flat-optics periodic nanogratings using vertically stacked WS₂-MoS₂ van der Waals heterostructures with type-II band alignment [6]. These engineered vdW structures support scalable applications in nanophotonics, energy harvesting, and photoconversion [7].

This work was supported by the NEST – Network 4 Energy Sustainable Transition – PNRR partnership.

References

1. M.C. Giordano et al. Adv. Mater. Interfaces, 10 (5), 2201408, 2023.

2. C. Mennucci et al. Adv. Opt. Mater. 9 (2), 2001408, 2021.

3. M. Bhatnagar et al., Nanoscale, 12, 24385, 2020.

4. M. Bhatnagar et al. ACS Appl. Mater. Interf., 13, 11, 13508, 2021

5. G. Ferrando et al. Nanoscale 15,4, 1953, 2023

6. M. Gardella et al. Small, 2400943, 2025

7. M. Gardella et al. RSC Appl. Interfaces, 1, 1001-1011, 2024

An array of closely spaced dipole-dipole coupled quantum emitters exhibits collective energy shifts as well as super- and sub-radiance with characteristic tailorable spatial radiation patterns. We identify a sub-wavelength sized ring of exactly 9 identical dipoles with an identical absorbing atom at the center as the most efficient configuration to deposit incoming photon energy to the center.

For very tight dimension below a tenth of a wavelength, a full quantum master equation description exhibits a larger enhancement than predicted from a classical coupled dipole model. Adding gain to such systems allows to design minimalistic light sources with tailorable properties. Examples are mirrorless lasers, non-classical light sources for single or entangled pair photon generation

Such ring shaped structures could be the basis of a new generation of highly efficient and selective nano antennas for single photon detectors of microwaves, infrared or optical frequencies their unexpected properties could be an important piece towards understanding the efficiency of natural light harvesting molecules.

More complex structures of dipole rings are also predicted for robust and low loss long range transport on the single excitation level.

Refs: Optica Quantum 2 (2), 57-63 & Applied Physics Letters 119.2 (2021).

Rare earth (RE) emitters are key materials for efficient light generation due to their chemical and thermal stability combined with high photoluminescence quantum yield (PLQY). Herein, we show that the integration of RE nanocrystals or nanophosphors into designed optical environments allows fine control over the properties of the emitted light without changing their chemical composition or compromising their efficiency. In particular, we theoretically and experimentally study the influence of the optical environment on the radiative decay rate of RE transitions in luminescent nanoparticles forming a thin film, and provide a way to rationally tune the spontaneous decay rate and hence the PLQY in an ensemble of luminescent nanoparticles. Then, we demonstrate a versatile and scalable method to fabricate periodically corrugated nanophosphor surface patterns that exhibit strongly polarized and directional visible light emission. A combination of inkjet printing and soft lithography techniques is used to obtain arbitrarily shaped light-emitting motifs. Such pre-designed luminescent patterns, in which the polarization and angular characteristics of the emitted light are determined and finely tuned by the surface relief, can be used as anti-counterfeiting labels, as these two specific optical features provide additional means to identify any unauthorized or counterfeit copy of the protected item.

Phosphor-converted micro-LEDs (pc micro-LEDs) are envisioned as next-generation high-brightness self-emissive display pixels for near-eye applications such as AR/VR glasses and smartwatches. However, these application settings impose stringent constraints on pixel density, emission efficiency, and angular control, necessitating advanced nanophotonic design strategies. In this work, we first present PyRAMIDS, a computational toolbox for efficient optical modelling in stratified media. Using this tool, we design spacer geometries within the LED stack to promote waveguiding characteristics in the phosphor layer. Experimentally, by integrating periodic corrugations to extract the guided emission, we demonstrate up to a threefold enhancement in pixel brightness compared to conventional LED architectures, validating the efficacy of our proposed approach. Finally, we implement an inverse design-based genetic algorithm to realize compact, aperiodic metasurfaces for emission pattern control, compatible with pixel densities exceeding 10,000 PPI displays - an essential requirement for seamless visual experiences in future smart glasses.

We present a complete framework of stochastic thermodynamics for a single-mode linear optical cavity driven on resonance. The significance of our results is two-fold. On one hand, our work positions optical cavities as a unique platform for fundamental studies of stochastic thermodynamics. On the other hand, our work paves the way for improving the energy efficiency and information processing capabilities of laser-driven optical resonators using a thermodynamics based prescription.

Probing single-protein dynamics at the molecular level is crucial for understanding conformational changes and functional mechanisms. Surface-enhanced Raman spectroscopy (SERS) offers a promising label-free approach to study protein. However, traditional SERS substrates face challenges due to the large size of proteins that are too large to fit in conventional hotspots. Here, we demonstrate that coupled plasmonic nanocavities enhance the Raman scattering up to 10^8 in an unconfined area. We harness the enhanced fields to reveal the dynamics of a single protein by observing time-dependent changes in the Raman spectrum, which is a unique probe of the secondary structure of the protein. We study the effect of the pH and the surface charge of the substrate on the conformation of a single protein of bovine serum albumin (BSA). The dominant secondary structure of BSA is α-helix at pH 7, while at pH 3 and 10, more β sheet and random structure are observed. We use principal component analysis to classify the proteins on the basis of their secondary structure. This work establishes a new possibility of studying large biomolecules and proteins crucial for biomedical applications and understanding the biological functions of proteins and the origin of diseases.