On-chip cavity electro-acoustics using lithium niobate phononic crystal resonators

TL;DR

This paper demonstrates on-chip cavity electro-acoustic control using lithium niobate phononic crystal resonators, enabling atomic-like phononic mode transitions, non-reciprocal frequency conversions, and potential quantum acoustics applications.

Contribution

It introduces a novel on-chip platform for cavity electro-acoustics with electrically modulated phononic crystal resonators on lithium niobate, achieving atomic-like mode control and non-reciprocal signal processing.

Findings

Achieved Autler-Townes splitting, Stark shift, and Rabi oscillations with a maximum cooperativity of 4.18.

Demonstrated non-reciprocal frequency conversions with up to 20 dB isolation.

Tuned non-reciprocity by adjusting the time delay between modulating pulses.

Abstract

Mechanical systems are pivotal in quantum technologies because of their long coherent time and versatile coupling to qubit systems. So far, the coherent and dynamic control of gigahertz-frequency mechanical modes mostly relies on optomechanical coupling and piezoelectric coupling to superconducting qubits. Here, we demonstrate on-chip cavity electro-acoustic dynamics using our microwave-frequency electrically-modulated phononic-crystal (PnC) resonators on lithium niobate (LN). Leveraging the high dispersion of PnC, our phononic modes space unevenly in the frequency spectrum, emulating atomic energy levels. Atomic-like transitions between different phononic modes are achieved by applying electrical fields to modulate phononic modes via nonlinear piezoelectricity of LN. Among two modes, we demonstrate Autler-Townes splitting (ATS), alternating current (a.c.) Stark shift, and Rabi oscillation with a maximum cooperativity of 4.18. Extending to three modes, we achieve non-reciprocal frequency conversions with an isolation up to 20 dB. Nonreciprocity can be tuned by the time delay between the two modulating pulses. Our cavity electro-acoustic platform could find broad applications in sensing, microwave signal processing, phononic computing, and quantum acoustics.