title: All-optical highly sensitive akinetic sensor for ultrasound detection and photoacoustic imaging.
abstract: A novel all-optical akinetic ultrasound sensor, consisting of a rigid, fiber-coupled Fabry-Pérot etalon with a transparent central opening is presented. The sensing principle relies exclusively on the detection of pressure-induced changes of the refractive index in the fluid filling the Fabry-Pérot cavity. This enables resonance-free, inherently linear signal detection over a broad bandwidth. We demonstrate that the sensor achieves a exceptionally low peak noise equivalent pressure (NEP) values of 2 Pa over a 20 MHz measurement bandwidth (without signal averaging), while maintaining a flat frequency response, and a detection bandwidth up to 22.5 MHz (-6 dB). The measured large full field of view of the sensor is 2.7 mm × 1.3 mm and the dynamic range is [Formula: see text] or 63 dB at 20 MHz bandwidth. For different required amplitude ranges the upper amplitude detection limit can be customized from at least 2 kPa to 2 MPa by using cavity mirrors with a lower optical reflectivity. Imaging tests on a resolution target and on biological tissue show the excellent suitability of the akinetic sensor for optical resolution photoacoustic microscopy (OR-PAM) applications.
authors.affiliation: XARION Laser Acoustics GmbH, Ghegastraße 3, 1030, Vienna, Austria; Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Gürtel 18-20, AKH 4L, 1090, Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Preisser
authors.affiliation: XARION Laser Acoustics GmbH, Ghegastraße 3, 1030, Vienna, Austria; Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Gürtel 18-20, AKH 4L, 1090, Vienna, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Rohringer
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Gürtel 18-20, AKH 4L, 1090, Vienna, Austria.
authors.forename: Mengyang
authors.initials: M
authors.lastname: Liu
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Gürtel 18-20, AKH 4L, 1090, Vienna, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Kollmann
authors.affiliation: XARION Laser Acoustics GmbH, Ghegastraße 3, 1030, Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Zotter
authors.affiliation: XARION Laser Acoustics GmbH, Ghegastraße 3, 1030, Vienna, Austria.
authors.forename: Balthasar
authors.initials: B
authors.lastname: Fischer
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Gürtel 18-20, AKH 4L, 1090, Vienna, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Drexler
keywords: (040.0040) Detectors; (120.0120) Instrumentation, measurement, and metrology; (170.0110) Imaging systems; (170.0170) Medical optics and biotechnology; (170.0180) Microscopy; (170.5120) Photoacoustic imaging; (170.7170) Ultrasound