Time-Resolved Cavity Nano-Optomechanics in the 20-100 GHz range

TL;DR

This paper demonstrates the optical control of high-frequency (20-100 GHz) mechanical modes in nano-optomechanical pillar cavities, revealing strong coupling, high Q-factors at room temperature, and potential for quantum applications.

Contribution

It introduces a method to access and control high-frequency mechanical modes in nano-optomechanical resonators, surpassing previous GHz limitations and enabling quantum optomechanics at room temperature.

Findings

Achieved control of 20-100 GHz mechanical modes.

Observed high Q-frequency products above 10^14 at room temperature.

Detected sideband generation in the optomechanical response.

Abstract

Applications of cavity optomechanics span from gravitational wave detection to the study of quantum motion states in mesoscopic mechanical systems. The engineering of resonators supporting strongly interacting mechanical and optical modes is central to these developments. However, current technological and experimental approaches limit the accessible mechanical frequencies to a few GHz, imposing hard constraints on quantum mechanical studies. Here we demonstrate the optical control of 20-100~GHz mechanical modes confined in the three dimensions within semiconductor nano-optomechanical pillar cavities. We use a time-resolved transient optical reflectivity technique and access both the energy spectrum and dynamics of the mechanical modes at the picosecond timescale. A strong increase of the optomechanical coupling upon reducing the pillar size is observed together with unprecedent room temperature Q-frequency products above $10^{14}$. The measurements also reveal sideband generation in the optomechanical response. Such resonators can naturally integrate quantum wells and quantum dots, enabling novel applications in cavity quantum electrodynamics and high frequency nanomechanics.