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DESIGNING LIGHT WITH PHOTONICS
I am passionate about understanding how light interacts with complex photonic structures and how these interactions can be harnessed to improve next-generation energy and optoelectronic technologies. My research focuses on the computational design and analysis of resonant dielectric nanophotonic systems, with a particular emphasis on enhancing light management in perovskite solar cells. Using electromagnetic simulations and analytical modelling, I study whispering-gallery mode resonators, photonic molecules, Fabry–Pérot cavities, and dielectric Bragg reflector structures to explore optical mode hybridization, resonance engineering, and light–matter interactions. I enjoy combining numerical modelling with physical insight to understand the mechanisms that govern optical phenomena and to develop innovative photonic architectures for practical applications.
RESEARCH HIGHLIGHTS
Twirling around the performance of perovskite solar cell architectures using resonators.
Whispering Gallery Modes
Whispering Gallery Modes
With the aid of 3D finite difference time-domain simulations, model configurations for CsPbI3 thin-film solar cell devices that include periodically arranged TiO2 microspheres, exhibiting resonating whispering gallery modes, are proposed. The TiO2 microspheres present, either immersed in perovskite or coated with perovskite layer, between the electron- and hole-transport layers show enhanced current-conversion efficiency. The presence of WGMs lead to enhancement in the absorption of CsPbI3 layer. Different designs are examined for deciding the appropriate position of WGM exhibiting spheres with respect to thin-film perovskite solar cell (PSC) featuring back reflector and optimized anti-reflectance coating. Since the incoupling element is lossless, energy stored in microspheres is absorbed efficiently by the underlying active material, directly contributing to the increment in the current density of the solar cell. Thus, the devices show a higher current density of 23.62 mA cm−2, while that in planar PSC device shows current density of 13.68 mA cm−2, for the same thickness of perovskite layer. This leads to more than 70% enhancement in the short-circuit current density than the conventional PSCs device of similar size.
Fabry-Pérot Modes
Fabry-Pérot Modes
Rhombus-shaped thin Rb3Sb2I9 microcrystals are investigated for their photoluminescence (PL) spectral properties. The spectra show broad self-trapped excitonic emissions with superimposed periodic spectral modulations. Through numerical analysis and an appropriate interference function model, we demonstrate that these spectral modulations arise from Fabry-Perot (FP) interferences, which are rarely observed in halide perovskites. The microcrystal with thin, large flat facets acts as an FP resonating cavity with two parallel mirror surfaces that capture and resonate the incident light throughout the crystal. The FP resonances have been confirmed through 3D full-field finite difference time domain simulations, which reveal variations in electric field eigenmodes with different crystal thicknesses and incident wavelengths. These self-resonating highly sensitive FP microcrystals have potential applications in various lead-free optoelectronic devices, including optical sensors, and as absorption enhancers in perovskite solar cells.
Photonic Molecules
Photonic Molecules
Coupled optical microresonators provide a versatile platform for engineering light-matter interactions through hybridized optical supermodes, enabling applications in integrated photonics, sensing, and spectral filtering. While whispering gallery mode coupling in photonic molecules has been extensively explored, a systematic understanding of how cavity topology and dielectric engineering collectively govern the spectral organization of high-index photonic molecules remains limited. Here, we present a unified numerical and analytical investigation of optical supermode formation in pristine and perovskite-coated TiO2 photonic molecules. Using finite-difference time-domain simulations in conjunction with a single-mode tight-binding model, we systematically investigate linear chains and compact clusters of coupled micro-resonators and demonstrate that each molecular topology exhibits distinct spectral fingerprints governed by the number, symmetry, and connectivity of the constituent cavities. Furthermore, we show that dielectric-shell engineering introduces an independent degree of freedom for tailoring inter-cavity coupling, enabling controlled spectral compression with up to an 80 % reduction in free spectral range while preserving high-quality resonances (Q ~ 10^3). The analytical model accurately reproduces the observed mode splitting, modal redistribution, and topology-dependent supermode evolution, establishing a direct relationship between molecular geometry, optical coupling, and spectral response. These results provide a general framework for engineering optical supermodes in high-index photonic molecules and establish dielectric-shell tuning as a powerful strategy for designing compact resonant photonic architectures for sensing, spectral engineering, and integrated photonic devices.
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