GHz guided optomechanics in planar semiconductor microcavities

TL;DR

This paper presents a monolithic GHz semiconductor optomechanical platform using a planar microcavity with embedded quantum wells, enabling high-Q acoustic waveguides and strong optomechanical interactions for quantum control.

Contribution

It introduces a novel GHz optomechanical system based on a microcavity with guided acoustic phonons and demonstrates coherent coupling of acoustic modes at different depths.

Findings

High-Q acoustic waveguides at >6 GHz with Q~10^5

Significant modulation of quantum well photoluminescence

Coherent coupling of acoustic modes across depths

Abstract

Hybrid opto, electro, and mechanical systems operating at several GHz offer extraordinary opportunities for the coherent control of opto-electronic excitations down to the quantum limit. We introduce here a monolithic platform for GHz semiconductor optomechanics based on electrically excited phonons guided along the spacer of a planar microcavity (MC) embedding quantum well (QW) emitters. The MC spacer bound by cleaved lateral facets acts as an embedded acoustic waveguide (WG) cavity with a high quality factor ($Q\sim10^5$) at frequencies well beyond 6~GHz, along which the acoustic modes live over tens of $\mu$s. The strong acoustic fields and the enhanced optomechanical coupling mediated by electronic resonances induce a huge modulation of the energy (in the meV range) and strength (over 80\%) of the QW photoluminescence (PL), which, in turn, becomes a sensitive local phonon probe. Furthermore, we show the coherent coupling of acoustic modes at different sample depths, thus opening the way for phonon-mediated coherent control and interconnection of three-dimensional epitaxial nanostructures.