Efficient bidirectional piezo-optomechanical transduction between microwave and optical frequency

TL;DR

This paper presents a highly efficient on-chip piezo-optomechanical transducer enabling bidirectional microwave-optical conversion with significant improvements over previous methods, advancing quantum and classical information processing.

Contribution

The work introduces a novel transducer design that overcomes previous limitations, achieving nearly three orders of magnitude higher conversion efficiency and demonstrating effective acousto-optic modulation.

Findings

Bidirectional conversion efficiency of 10^-5 with red-detuned pump.

Conversion efficiency of 5.5% with blue-detuned pump at 323 microwatts.

Acousto-optic modulation with V_pi = 0.02 V.

Abstract

Efficient interconversion of both classical and quantum information between microwave and optical frequency is an important engineering challenge. The optomechanical approach with gigahertz-frequency mechanical devices has the potential to be extremely efficient due to the large optomechanical response of common materials, and the ability to localize mechanical energy into a micron-scale volume. However, existing demonstrations suffer from some combination of low optical quality factor, low electrical-to-mechanical transduction efficiency, and low optomechanical interaction rate. Here we demonstrate an on-chip piezo-optomechanical transducer that systematically addresses all these challenges to achieve nearly three orders of magnitude improvement in conversion efficiency over previous work. Our modulator demonstrates acousto-optic modulation with $V_{\pi} = {0.02}$ V. We show bidirectional conversion efficiency of $10^{-5}$ with ${3.3}$ microwatts red-detuned optical pump, and $5.5\%$ with $323$ microwatts blue-detuned pump. Further study of quantum transduction at millikelvin temperatures is required to understand how the efficiency and added noise are affected by reduced mechanical dissipation, thermal conductivity, and thermal capacity.