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Adrien Debacq

Publications and source records attributed to Adrien Debacq.

4 recordsLinked to original sources
arXiv2026

Impedance-controlled Laser Dynamics in Near-Zero Index Media

Near-zero-index (NZI) media have been explored for controlling spontaneous emission, but their impact on stimulated emission and lasing properties remains unexplored within their different classes, i.e., epsilon-near-zero (ENZ), mu-near-zero (MNZ), or epsilon-and-mu-near-zero (EMNZ). Here, we show theoretically that lasing emission depends on the class of NZI medium and can be controlled through its impedance. The major difference, as compared to conventional laser media, arises from the incorporation of dispersive electric and magnetic properties in the derivation of the Maxwell Boch equations. In this framework, the analysis of laser rate equation reveals that the ENZ class, with high impedance, can reduce the lasing threshold through enhanced electric-field interaction. Numerical simulations further show that the NZI class also governs the spectral response: whereas ENZ and MNZ classes suffer from multimode emission, the EMNZ class preserves single-mode emission.

physics.optics↗
arXiv2026

Universal framework for the design of near-zero refractive index photonic crystals

Near-zero-index (NZI) media are of great interest for controlling light-matter interactions, but homogeneous NZI materials in the telecom band remain limited and often suffer from significant losses. Photonic crystals provide an attractive alternative due to their tunability and use of low-loss constituent materials. This work presents a predictive framework for designing epsilon-near-zero (ENZ), mu-near-zero (MNZ), and epsilon-and-mu-near-zero (EMNZ) photonic crystals. We demonstrate an equivalence between Dirac cones and EMNZ behavior, showing that a Dirac cone at the Gamma point is both necessary and sufficient to obtain an effective EMNZ response under normal incidence. This result implies that the presence of a Dirac cone fully determines the NZI response of a photonic crystal, independent of the material composition. The prediction is based on mode symmetry universality and effective medium theory. The approach enables switching between ENZ-MNZ and EMNZ regimes through geometric tuning of the unit cell. It is validated on triangular and rectangular lattices. Overall, this work provides a predictive design strategy for NZI photonic crystals, replacing trial-and-error optimization. It may also impact metamaterials in the telecom regime and applications in quantum communication.

physics.optics↗
arXiv2025

Long-range quantum entanglement in dielectric mu-near-zero metamaterials

Entanglement is paramount in quantum information processing. Many quantum systems suffer from spatial decoherence in distances over a wavelength and cannot be sustained over short time periods due to dissipation. However, long range solutions are required for the development of quantum information processing on chip. Photonic reservoirs mediating the interactions between qubits and their environment are suggested. Recent research takes advantage of extended wavelength inside near-zero refractive index media to solve the long-range problem along with less sensitivity on the position of quantum emitters. However, those recent proposals use plasmonic epsilon near-zero waveguides that are intrinsically lossy. Here, we propose a fully dielectric platform, compatible with the Nitrogen Vacancy (NV) diamond centers on-chip technology, to drastically improve the range of entanglement over 17 free-space wavelengths, or approximatively 12.5 microns, using mu near-zero metamaterials. We evaluate transient and steady state concurrence demonstrating an order of magnitude enhancement compared to previous works. This is, to the best of our knowledge, the first time that such a long distance is reported using this strategy. Moreover, value of the zero time delay second order correlation function g_12^((2)) (0) are provided, showing antibunching signature correlated with a high degree of concurrence.

physics.optics↗