Biased electro-statically tunable buckled-dome etalon (BEST BuDE) optically transparent ultrasound transducers

Fabry-Perot etalons intended for detecting ultrasound have traditionally been limited by their reliance on narrow-linewidth tunable wavelength interrogation sources, which complicates large-array operation. Furthermore, most conventional ultrasound transducers are not optically transparent, restricting their use in applications such as photoacoustic imaging. Here, we present transparent, biased electrostatically, tunable buckled-dome etalon ultrasound transducers, a new class of microfabricated plano-concave Fabry-Perot etalon devices that integrate an electronic tuning mechanism with the exquisite sensitivity synonymous with some optical-based ultrasound transducers. This enables device-level spectral tuning for improving sensitivity or dynamic range, supporting the long-term vision of single-source parallel interrogation of multiple etalons within an array. These sensors achieve a noise-equivalent pressure as low as 1.4 Pa for devices of around 90 μm in diameter.