Seminar: Ultrasensitive ultrasound sensing with integrated optical microresonators

Title:  Ultrasensitive ultrasound sensing with integrated optical microresonators

Speaker: Dr Beibei Li,  Professor, Institute of Physics, Chinese Academy of Sciences, China

Abstract:
Ultrasound sensing is widely adopted in various applications, including medical imaging, non-destructive testing, underwater acoustics, and industrial process monitoring. Conventional ultrasound transducers, typically based on piezoelectric materials, have been widely used in these applications. However, these transducers face challenges in terms of miniaturization, integration, and sensitivities, which restrict their applications in scenarios that require compactness and high resolutions. Recently, ultrasound sensors based on optical microcavities have been developed, which provide the advantages of high sensitivities, broad bandwidth, low power consumption, and chip-integration capabilities. However, it is challenging to achieve high sensitivity using integrated optical microresonators.
In this work, we demonstrate a novel integrated, high-sensitivity optomechanical ultrasound sensor (Figs. 1a-1c) consisting of a suspended SiO₂ membrane and an embedded Si₃N₄ microring resonator. Due to the mechanical resonance enhanced response of the SiO₂ membrane and the optical resonance enhanced readout sensitivity of the high-Q Si₃N₄ microring resonator, this sensor achieved a NEP of 9.6 nPa Hz^-1/2 in the water environment (Fig. 1d). We further apply the sensor for ultrasound imaging in water, achieving a spatial resolution of 1.34 mm (Fig. 1e). This fully integrated, high-sensitivity ultrasound sensor opens new possibilities for a range of applications such as underwater ultrasound imaging, photoacoustic imaging, etc.

Meeting URL:
https://oist.zoom.us/j/95382321309?pwd=rfVbn4zd2NBR2DLL0zYAN3axDTv1HW.1&from=addon

Meeting ID: 953 8232 1309

Passcode: 589120