Integrated phononic waveguide on thin-film lithium niobate on diamond

TL;DR

This paper presents the development and characterization of integrated phononic waveguides on thin-film lithium niobate on diamond, demonstrating efficient phonon transmission at cryogenic temperatures for quantum applications.

Contribution

It introduces a novel transfer-printed lithium niobate on diamond platform for phononic waveguides, combining piezoelectricity with diamond's properties for quantum systems.

Findings

Achieved -5.8 dB insertion loss at 4 K

Demonstrated >50% transducer efficiency at 2.8 GHz

Characterized phononic delay line at cryogenic temperatures

Abstract

We demonstrate wavelength-scale phononic waveguides formed by transfer-printed thin-film lithium niobate (LN) on bulk diamond (LNOD), a material stack that combines the strong piezoelectricity of LN with the high acoustic velocity and color-center compatibility of diamond. We characterize a delay line based on a 100 micron long phononic waveguide at room and cryogenic temperatures. The total insertion loss through the device at 4 kelvin is -5.8 dB, corresponding to a >50% transducer efficiency, at a frequency of 2.8 gigahertz. Our work represents a step towards phonon-mediated hybrid quantum systems consisting of strain-sensitive color centers in diamond.