arXiv subjects

Faraz Ahmed Inam

Publications and source records attributed to Faraz Ahmed Inam.

4 recordsLinked to original sources

arXiv2026

Dynamical control of light-matter interaction through coherent multipolar scattering in broken symmetry metasurfaces

Achieving control over spontaneous emission by tailoring light-matter interactions is a key objective in quantum nanophotonics. Metasurfaces composed of high-refractive-index resonators like silicon (Si) provide a low-loss platform that supports a variety of strong electric and magnetic multipolar resonances, offering new opportunities to tailor the local density of optical states (LDOS). This work employs phase-resolved multipolar analysis to investigate spontaneous-emission control in symmetry-broken dielectric metasurfaces composed of Si cuboid and disk resonators. Controlled in-plane geometrical asymmetry enables hybridization between magnetic dipole (MD) and magnetic quadrupole (MQ) modes, whose coherent interaction modifies the local density of optical states (LDOS). Symmetry-broken dielectric metasurfaces are closely related to quasi-bound states in the continuum (quasi-BICs) and Fano-resonant systems, where geometrical perturbations promote coupling between weakly radiative and bright resonances. From this perspective, the observed MD-MQ hybridized states may be understood as a near-field and multipolar manifestation of symmetry-broken quasi-BIC physics. The resulting coherent magnetic multipolar interaction produces strong near-field localization and substantial spontaneous-emission enhancement for embedded emitters. For Erbium ions in broken-symmetry Si metasurfaces operating near 1.54 um, the analysis reveals pronounced enhancement associated with resonant magnetic multipolar coupling. These results establish magnetic multipolar interference as a physically transparent mechanism for emission control in low-loss dielectric metasurfaces and provide useful design guidelines for integrated quantum photonic devices.

physics.optics↗

arXiv2025

Photo-luminescence properties of ion implanted Er3+-defects in 4H-SiCOI towards integrated quantum photonics

Colour centres hosted in solid-state materials such as silicon carbide and diamond are promising candidates for integration into chip-scale quantum systems. Specifically, the incorporation of these colour centres within photonic integrated circuits may enable precise control over their inherent photo-physical properties through strong light-matter interaction. Here, we investigate ion-implanted erbium ($\text{Er}^{3+}$) defects embedded in thin-film 4H-silicon-carbide-on-insulator (4H-SiCOI). Optimized implantation conditions and thermal annealing processes designed to enhance the emission characteristics of the $\text{Er}^{3+}$-defect are reported. By examining key properties such as photoluminescence intensity, optical lifetime, and polarization, we present an analysis of ensemble $\text{Er}^{3+}$-defects within 4H-SiCOI, providing insights into their potential for future quantum applications.

physics.optics↗

arXiv2023

Mie-scattering controlled all-dielectric resonator-antenna for bright and directional point dipole emission

Designing a deterministic, bright, robust, room temperature stable, on-demand solid-state single photon source has been a major demand in the field of quantum-photonics. For this, various single-photon resonator and antenna schemes are being actively explored. Here, using the Cartesian multi-polar decomposition of the excited Mie-scattering moments, we present the design of a all-dielectric coupled-dipolar antenna comprising of two dielectric (Tin-oxide, TiO$_2$) cylinders sandwiching a nanodiamond based nitrogen-vacancy (NV$^-$) center trapped in a poly-vinyl alcohol (PVA) matrix. The Mie-scattering resonant cavity formed in the middle PVA layer provides more than an order of magnitude decay rate or Purcell enhancement. The balancing of the electric and magnetic dipolar moments (a phenomenon commonly known as the Kerker condition) of the coupled TiO$_2$ cylinders under NV$^-$ dipole excitation, provides significant directionality to the radiation pattern. Using a collection lens with a numerical aperture (NA) of 0.9 the vertical collection efficiency (VCE) was observed to be around 80\% at the NV$^-$ center's zero-phonon line wavelength.

physics.optics↗

arXiv2023

Silicon Carbide Metasurfaces for Controlling the Spontaneous Emission of Embedded Color Centers

While electric and magnetic dipolar resonances in SiC have been studied in the far-infrared, they have not been studied in the near infrared. Here we show for the first time that electromagnetic Mie-scattering moments within SiC metasurfaces can control the spontaneous emission process of point defects in the near infrared. Using SiC nanopillars based metasurfaces, we theoretically demonstrate a control over the spontaneous emission rate of embedded color-centers by using the coherent superposition of the electric dipolar and magnetic quadrupolar electromagnetic Mie-scattering moments of the structure. More than an order of magnitude emission/decay rate enhancement is obtained with the maximum enhancement close to 30. We also demonstrate that the relative phase of the Mie-scattering moments helps in controlling the emission directionality. SiC metasurfaces in the spectral range of color centres, from the visible to the near infrared, can be used to control the confinement and directionality of their spontaneous emission, increasing the opportunities to study light-matter interaction and to advance quantum photonic and quantum sensing device integration.

physics.optics↗