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Ultrasound point detectors in the silicon photonics platform for high frequency optoacoustic tomography (Conference Presentation)
Author(s): Rami Shnaiderman; Georg Wissmeyer; Héctor Estrada; Daniel Razansky; Qutaiba Mustafa; Andriy Chmyrov; Vasilis Ntziachristos

Paper Abstract

Acoustic imaging modalities such as multispectral optoacoustic tomography (MSOT) have recently matured to a point which allows retrieval of anatomical, molecular and dynamic information with resolutions of several tens of microns These advancements are going hand in hand with the continuous development of ultrasound detectors. Yet, the traditional piezoelectric transducers have a distinct disadvantage: the detector size is proportional to its sensitivity. This limits miniaturization and prevents the development of point-like detectors as well as the subsequent construction of ultra-dense detector arrays. Consequently, research has shifted towards all-optical ultrasound detectors, such as Fabry-Pérot resonators, where miniaturization does not affect detector sensitivity. In this context, we present a novel optical resonator on a silicon chip with a sensing area of 220 x 500 nm that - to the best of our knowledge – is the smallest ultrasound detector ever created. These dimensions are 77 and 34 times smaller than the acoustic wavelength at the central detection frequency, hence our detector is truly a point detector. Using the scalable silicon photonics platform we constructed an array of eight detectors. The archived density of 125 detectors/mm2 is larger by orders of magnitude compared to arrays of piezoelectric and capacitive micromachined ultrasound transducers. We describe the working principle of the detector and characterize its sensitivity, spatial response, and bandwidth. We demonstrate its applicability for optoacoustic tomography and perform the first SOI based tomography ever reported, by imaging micron-sized phantoms at light fluences well below the ANSI limit for human skin.

Paper Details

Date Published: 4 March 2019
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Proc. SPIE 10878, Photons Plus Ultrasound: Imaging and Sensing 2019, 108780P (4 March 2019); doi: 10.1117/12.2510712
Show Author Affiliations
Rami Shnaiderman, Technische Univ. München (Germany)
Georg Wissmeyer, Technische Univ. München (Germany)
Héctor Estrada, Technische Univ. München (Germany)
Daniel Razansky, Technische Univ. München (Germany)
Qutaiba Mustafa, Technische Univ. München (Germany)
Andriy Chmyrov, Technische Univ. München (Germany)
Vasilis Ntziachristos, Technische Univ. München (Germany)


Published in SPIE Proceedings Vol. 10878:
Photons Plus Ultrasound: Imaging and Sensing 2019
Alexander A. Oraevsky; Lihong V. Wang, Editor(s)

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