Isabella He | Searcharxiv

arXiv2026

Localized high-Q resonances enable electrically defined beam steering in lithium niobate metasurfaces

High-speed beam steering for LiDAR and optical communication requires independent, reconfigurable control of optical phase. We demonstrate a metasurface combining lithium niobate's Pockels effect with high-Q (Q > 1700) silicon guided-mode resonance nanoantennas whose localized resonances allow individual electro-optic control at a 1 $μ$m pitch. Identical arrays steer light to 53.5$^\circ$ or 32.4$^\circ$, with the angle set by the bias pattern rather than antenna geometry. We measure 18.0% 0th-order modulation depth, 0.09% of incident power in the steered order, and a 940 MHz detected modulation bandwidth. Mode-overlap analysis shows how inter-element coupling limits usable Q, providing design rules for compact, high-speed beam steering.

physics.optics↗

arXiv2024

Chip-scale monolithic optoelectronic voltage boost conversion

Voltage conversion is a fundamental electronic process critical to engineered systems across a wide spectrum of applications and spanning many orders of magnitude in scale. Conventional approaches like transformers and charge pumps perform well in specific contexts but face fundamental limitations to miniaturization, electromagnetic interference, and voltage range. Here we present a chip-scale, fully integrated monolithic, non-switching optoelectronic voltage conversion platform capable of high gain, bootstrap-free boost-mode operation across several orders of magnitude in power density and voltage scale. Using the bidirectional coupling between LEDs and PV cells with identical active layer materials, our chip-scale, single-die strategy eliminates Stokes losses while improving key parameters like physical footprint, series resistance, and photon leakage by orders of magnitude over implementations using multiple packaged, discrete components. Moreover, by exploiting the large étendue of NIR-transparent semi-insulating InP substrates and the atomically smooth, void-free interface of lattice-matched epitaxial growth, simulations indicate that our InGaAsP architecture's photon transport simultaneously provides a > 60x increase in current density and > 50x reduction in non-radiative recombination losses compared with a multiple-die solution while simultaneously reducing fabrication complexity and improving mechanical robustness. We experimentally demonstrate a boost gain of 3.8x in an 8x8 mm$^2$ InGaAs-on-InP chip while validating key aspects of the voltage conversion platform.

physics.optics↗