Transverse magnetic routing of light emission in hybrid plasmonic-semiconductor nanostructures: Towards operation at room temperature

TL;DR

This study investigates the temperature-dependent control of light emission directionality in hybrid plasmonic-semiconductor nanostructures, demonstrating magnetic field-induced routing at low temperatures and proposing designs for operation closer to room temperature.

Contribution

The paper provides experimental and theoretical insights into magnetic routing of light emission in hybrid structures and introduces alternative designs for higher temperature operation.

Findings

Strong emission directionality of 15% at 20 K in magnetic structures

Directionality decreases to 4% at 45 K as magnetic susceptibility drops

Proposed non-magnetic structures can achieve 5% directionality below 200 K

Abstract

We study experimentally and theoretically the temperature dependence of transverse magnetic routing of light emission from hybrid plasmonic-semiconductor quantum well structures where the exciton emission from the quantum well is routed into surface plasmon polaritons propagating along a nearby semiconductor-metal interface. In II-VI and III-V direct band semiconductors the magnitude of routing is governed by the circular polarization of exciton optical transitions, that is induced by a magnetic field. For structures comprising a (Cd,Mn)Te/(Cd,Mg)Te diluted magnetic semiconductor quantum well we observe a strong directionality of the emission up to 15% at low temperature of 20 K and magnetic field of 485 mT due to giant Zeeman splitting of holes mediated via the strong exchange interaction with Mn$^{2+}$ ions. For increasing temperatures towards room-temperature the magnetic susceptibility decreases and the directionality strongly decreases to 4% at T = 45 K. We also propose an alternative design based on a non-magnetic (In,Ga)As/(In,Al)As quantum well structure, suitable for higher temperatures. According to our calculations, such structure can demonstrate emission directionality up to 5% for temperatures below 200 K and moderate magnetic fields of 1 T.