Fast Programming of In-Plane Hyperbolic Phonon Polariton Optics Through van der Waals Crystals using the Phase-Change Material In3SbTe2

TL;DR

This paper demonstrates a rapid, reconfigurable method for programming in-plane hyperbolic phonon polaritons using phase-change materials and optical laser pulses, enabling flexible control of polariton propagation and confinement.

Contribution

It introduces a novel optical programming approach for reconfiguring polariton structures in van der Waals crystals, improving speed and flexibility over traditional fabrication methods.

Findings

Successful reconfiguration of polariton structures using optical programming.

Comparable confinement and tuning to gold disk focusing.

Ability to tailor polariton confinement by reprogramming disk structures.

Abstract

The high directionality of hyperbolic phonon polaritons (HPhPs) has opened radically new ways to route and steer the flow of energy at the nanoscale. However, launching HPhPs requires fabricating efficient and precisely aligned polariton launching structures, which remains time-consuming and expensive with conventional nanofabrication approaches. Recently, using optical laser pulses, polariton launching structures have been programmed into the plasmonic phase-change material In3SbTe2. Here, we leverage this approach to reconfigure HPhPs by programming a variety of launching and confining nanostructures through {\alpha}-MoO3 flakes deposited onto In3SbTe2. Importantly, optical programming after flake deposition enables alignment of launching stripes to the [001]-axis of the flake, essential to control the directional polariton propagation. We showcase these capabilities in a variety of structures: i) an optically programmed disk, showing similar tuning ranges and confinement as focusing by gold disks; and ii) a cavity for in-plane HPhPs created by reconfiguring the single disk to a double disk structure, tailoring the confinement by simply reprogramming the disk distance. Our fabrication scheme offers fast turn-around times, flexible alignment and the opportunity to reconfigure the structures. Thus, it is a fast, efficient and versatile way to tailor propagation and confinement of highly directional polaritons on demand.