arXiv subjects

Jonathan Barolak

Publications and source records attributed to Jonathan Barolak.

6 recordsLinked to original sources

arXiv2026

Robust inverse design of non-periodic Bloch surface wave sensors

One-dimensional photonic crystals supporting Bloch surface waves (BSWs) have emerged as highly sensitive platforms for label-free refractometric sensing. However, the practical performance of these sensors is limited by their vulnerability to fabrication-induced thickness variations. In this Letter, we address this challenge by introducing a robust inverse design framework based on multi-objective genetic optimization. This framework jointly maximizes intensity sensitivity and resilience against manufacturing errors, demonstrating that non-periodic multilayers achieve inherently superior sensitivity-robustness trade-offs, with a pronounced gain in device resilience over conventional periodic designs. By analyzing the optimized designs, we uncover an intrinsic compensation mechanism that physically governs the trade-off and effectively stabilizes the sensor response against structural perturbations. By unlocking the expanded design space of non-periodic multilayers, our optimization strategy paves the way for the practical realization of next-generation BSW sensors.

physics.optics↗

arXiv2026

Polarization-Multiplexed Bloch Surface Wave Sensing of Single-Strand DNA Growth

Refractometric biosensing is a vital label-free tool for the real time detection and interaction analysis of biological and chemical substances. Nanophotonic platforms like Surface Plasmon Resonance (SPR) have played a critical role in providing refractometric sensing capabilities for clinical diagnostics and environmental monitoring. However, traditional systems operating in a single-polarization state cannot fully characterize complex optical properties such as birefringence, which is crucial to resolve many complex biological interactions. Although Bloch Surface Wave (BSW) sensors can support both TE and TM modes, a key capability SPR lacks, they have historically been implemented in single-mode configurations. In this paper, we present a polarization multiplexed BSW refractometric sensing system, simultaneously tracking the resonant wavelength shifts of both TE and TM BSW modes through time. Our technique was applied to investigate single-strand DNA growth during rolling circle amplification (RCA). To accurately recover the time-dependent birefringence, capturing dynamics of the DNA growth and orientation of its chains, we implemented a two-stage modeling approach based on the TMM. First, we utilized a wavelength-dependent surface sensitivity model, confining refractive index changes to the immediate layer above the crystal, to distinguish isotropic background dynamics from birefringent signals. Following the onset of RCA, we transitioned to a model that accounted for the vertical growth of the DNA layers in time. By fitting this model to the TE and TM resonant shifts, we monitor the growth rate of the single-strand DNA layer as well as the refractive index along the two polarization components. Our findings demonstrate the platform's ability to resolve the structural evolution of complex bimolecular interactions associated with conformational changes.

physics.optics↗

arXiv2025

Leveraging Low Index Contrast to Reduce the Polarization Anisotropy in One-Dimensional Photonic Crystals

One-dimensional photonic crystals (1DPCs) are widely used platforms for guiding, filtering, and enhancing light at the nanoscale. Traditionally, designs have favored high refractive index contrast to maximize the photonic band gap (PBG) size. Here, we demonstrate that low-index contrast systems offer a powerful and underexplored route to achieving improved optical functionalities. In particular, we show that low index contrast enables more closely aligned PBGs for transverse electric (TE) and transverse magnetic (TM) polarizations, allowing for broadband superposition of TE and TM Bloch Surface Waves (BSWs). As a demonstration of this functionality, we use this approach to design 1DPCs capable of generating planar superchiral fields for enhanced circular dichroism spectroscopy. To realize such structures, we use an automated design framework based on multi-objective genetic optimization. By comparing optimized designs in both high and low index contrast regimes, we find that low index contrast systems yield significantly greater overlap between the TE and TM BSW dispersion relations and exhibit a pronounced reduction in optical anisotropy - both of which contribute to enhanced optical chirality across the operational bandwidth. Furthermore, simulations reveal that these low index contrast structures offer improved robustness to fabrication tolerances and support a wider dynamic range of chiral analyte concentrations. In addition to their optical performance advantages, low-index contrast systems are naturally compatible with polymeric materials, which offer benefits such as low cost, sustainability, and mechanical flexibility. While this work focuses on mode alignment and its consequences for surface wave behavior, the underlying principles have broader implications for polarization-independent photonic technologies, including optical sensing, computing, and spectral filtering.

physics.optics↗

arXiv2025

Self-interfering high harmonic beam arrays driven by Hermite-Gaussian beams

The use of structured light to drive highly nonlinear processes in matter not only enables imprinting spatially-resolved properties onto short-wavelength radiation, but also opens alternative avenues for exploring the dynamics of nonlinear laser-matter interactions. In this work, we experimentally and theoretically explore the unique properties of driving high-order harmonic generation (HHG) with Hermite-Gaussian beams. HHG driven by Laguerre-Gauss modes results in harmonics that inherit the azimuthal Laguerre-Gauss modal structure, with their topological charge scaling according to orbital angular momentum conservation. In contrast, when HHG is driven by Hermite-Gauss beams, the harmonic modes do not show a direct correspondence to the driving modal profile. Our experimental measurements using HG$_{0,1}$ and HG$_{1,1}$ modes, which are in excellent agreement with our numerical simulations, show that the lobes of the Hermite-Gauss driving beams effectively produce a set of separate phase-locked harmonic beamlets which can interfere downstream. This self-interference, which can be adjusted through the relative position between the gas target and the driving beam focus, can be exploited for precision extreme-ultraviolet interferometry. We demonstrate a simple application to calibrate the dispersion of an extreme-ultraviolet diffraction grating. In addition, we show through simulations that the array of harmonic beamlets can be used as an illumination source for single-shot extreme-ultraviolet ptychography.

physics.optics↗

arXiv2020

Wavelength-multiplexed single-shot ptychography

Diagnostics capable of interrogating dynamics in harsh environments such as plasma have remained essentially unchanged in recent decades. Developments in advanced microscopy techniques will improve our understanding of the physics involved in these events. Recently developed single-shot ptychography (SSP) provides a pathway towards sophisticated plasma metrologies. Here we introduce wavelength-multiplexed single-shot ptychography (WM-SSP), which allows for hyperspectral, spatially and temporally resolved phase and amplitude contrast imaging. Furthermore, we introduce a novel probe constraint common to all wavelength multiplexed modalities in the single-shot geometry and present modifications to SSP that improve reconstruction fidelity and robustness. WM-SSP was experimentally realized and simulations show the technique's ability to deconvolve the electron and neutral densities within the plasma. WM-SSP will pave the way to a new generation of quantitative plasma imaging techniques.

physics.optics↗

arXiv2020

Three-Dimensional Single-Shot Ptychography

Here we introduce three-dimensional single-shot ptychography (3DSSP). 3DSSP leverages an additional constraint unique to the single-shot geometry to deconvolve multiple 2D planes of a 3D object. Numeric simulations and analytic calculations demonstrate that 3DSSP reconstructs multiple planes in an extended 3D object with a minimum separation consistent with the depth of field for a conventional microscope. We experimentally demonstrate 3DSSP by reconstructing orthogonal hair strands axially separated by 5 mm. Three-dimensional single-shot ptychography provides a pathway towards volumetric imaging of dynamically evolving systems on ultrafast timescales.

eess.IV↗