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Alireza Khalilian

Publications and source records attributed to Alireza Khalilian.

5 recordsLinked to original sources
arXiv2025

Multi-NA Metalens Array for Compact High-NA Microscopy

We demonstrate a CMOS-compatible silicon-rich nitride metalens array for visible microscopy at 660 nm. Three co-planar elements provide numerical apertures of 0.54, 0.92, and 0.97, enabling within-sample NA benchmarking without objective swaps. Imaging of annular cell monolayers labeled in the AF647 ZO-1 channel shows progressive sharpening of junctional edges and reduced blur with increasing NA, consistent with diffraction-limited scaling. The compact, planar platform supports direct integration with image sensors, offering a practical route to high-NA fluorescence bioimaging in space-constrained, low-cost systems.

physics.optics↗
arXiv2025

Design Optimized CMOS Compatible Hybrid Silicon MIM Waveguide Cavity for Label Free Sensing

We numerically design a hybrid plasmonic dielectric refractive index biosensor comprising ametal insulator metal (MIM) bus waveguide evanescently coupled to a silicon core resonator. The geometry is optimized with a genetic algorithm (GA) using Ansys Lumerical FDTD simulations, targeting maximal sensitivity and figure of merit while minimizing the resonance linewidth. The optimized device achieves a sensitivity of 1276 nm/RIU, a full width at half maximum (FWHM) of 11.89nm, a quality factor of 221, and a figure of merit of 107 RIU1 (defined as S/FWHM). These results demonstrate precise discrimination of small refractive index variations and support the sensors applicability to label free biochemical and medical diagnostics.

physics.ins-det↗
arXiv2025

Polarization-Resolved Chlorophyll Imaging for Non-Invasive Plant Tissue Assessment Using a Silicon-Rich Nitride Metalens Array

Polarization-sensitive imaging enhances contrast and reveals structural features in biological tissues that are often missed by intensity-based methods, but its adoption is limited by bulky optics. We present a compact silicon-rich nitride (SRN) metalens array for high-resolution, polarization-resolved imaging of plant tissue at the chlorophyll absorption peak (660\,nm). The array integrates orthogonally sensitive metalenses to simultaneously capture X- and Y-linearly polarized transmission images, enabling real-time, label-free assessment of plant microstructure and stress responses. Polarization fusion and difference mapping reveal structural anisotropy and pigment variation in both healthy and stressed leaves. The SRN metalens, designed via an inverse approach using birefringent meta-atoms and fabricated through CMOS-compatible processes, achieves a large numerical aperture, high transmission, and spectral alignment with biological absorbers. This work demonstrates the feasibility of compact, integrated polarization-resolved imaging, offering a scalable alternative to conventional systems. The approach holds potential for biomedical and agricultural applications, where detecting subtle polarization-dependent changes could enable early diagnosis and tissue characterization

physics.optics↗
arXiv2024

Polarization-based Metalenses with High Numerical Aperture and Focusing Efficiency Utilizing Silicon-rich Nitride

We explore the cutting-edge application of silicon-rich nitride (SRN) in the realm of high numerical aperture (NA) metalens design, focusing on the crucial role of pitch size optimization in amplifying lens efficiency through advanced simulations. Our investigation unveils how the exceptional tunable high refractive index of SRN can be harnessed to achieve significant advancements in metalens performance. By meticulously designing and simulating two innovative SRN-based metalenses - Mk1, with an NA of 0.9, reaching an impressive 75% focusing efficiency with full width at half maximum (FWHM) of 0.53λ, and Mk2, with an NA of 0.99, achieving a 42% efficiency while maintaining an FWHM of 0.48λ. We demonstrate the critical influence of reduced pitch size on enhancing efficiency. This study not only highlights the unparalleled potential of SRN in optimizing metalens efficiency but also represents a significant leap forward in the field of nanophotonics, offering new pathways for the development of highly efficient flat photonic devices.

physics.optics↗