Fast interrogation wavelength tuning for all-optical photoacoustic imaging

Optical detection of ultrasound for photoacoustic imaging provides a large bandwidth and high sensitivity at high acoustic frequencies. Therefore, higher spatial resolutions can be achieved using Fabry-Perot cavity sensors than conventional piezoelectric detection. However, fabrication constraints during the deposition of the sensing polymer layer require precise control of the interrogation beam wavelength to provide optimal sensitivity. This is commonly achieved by employing slowly tunable narrowband lasers as interrogation sources, hence limiting the acquisition speed. We propose instead to use a broadband source and a fast-tunable acousto-optic filter to adjust the interrogation wavelength at each pixel within a few microseconds. We demonstrate the validity of this approach by performing photoacoustic imaging with a highly inhomogeneous Fabry-Perot sensor. (c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

Optical detection of ultrasound for photoacoustic imaging using Fabry-Perot cavity sensors allows for higher spatial resolutions compared to conventional piezoelectric detection. However, precise control of the interrogation beam wavelength is required for optimal sensitivity. This study proposes the use of a broadband source and a fast-tunable acousto-optic filter to adjust the interrogation wavelength at each pixel within microseconds, overcoming fabrication constraints and improving acquisition speed.