Optoacoustic imaging using thin polymer étalon

Optical detection of ultrasound is a promising technique for high frequency imaging arrays. Detection resolution approaches the optical resolution, which can be on the order of the optical wavelength. We describe here an optical technique for ultrasound detection based on a thin $\left(10\mu \mathrm{m}\right)$ Fabry–Perot étalon optimized for high resolution imaging. The signal to noise ratio (SNR) approaches that of an ideal piezoelectric transducer over a $100\mathrm{MHz}$ bandwidth. Array functionality is demonstrated by scanning a probe beam along a line. Thermoelastic excitation was applied to generate acoustic waves in a test phantom containing a single “pointlike” source. An image of the source was reconstructed using signals acquired from the étalon detector array.