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Ring PMUT array based miniaturized photoacoustic endoscopy device

Dangi, A and Agrawal, S and Tiwari, S and Jadhav, S and Cheng, C and Datta, GR and Trolier-Mckinstry, S and Pratap, R and Kothapalli, S-R (2019) Ring PMUT array based miniaturized photoacoustic endoscopy device. In: Photons Plus Ultrasound: Imaging and Sensing 2019, 3 - 6 February 2019, San Francisco.

Full text not available from this repository.
Official URL: https://doi.org/10.1117/12.2510000


The first successful validation of a forward-looking Piezoelectric Micromachined Ultrasound Transducer (PMUT) ring array designed for photoacoustic endoscopic imaging applications is presented. PMUT ring arrays were fabricated with a 0.5 mm inner diameter, to allow insertion of an optical fiber for light delivery, and ~2.5 mm overall outer diameter. Each ring array consisted of 6 elements, with a total of 102 PMUT cells, or 17 cells per element. Each PMUT cell has a 100 μm diameter multi-layered diaphragm having a ~700 nm thick c-axis oriented aluminium nitride (AlN) thin film as the piezoelectric layer over a Si (handle layer) / SiO2 (1 μm) / Si (10 μm) / SiO2 (100 nm) / TiO2 (40 nm) / Pt (150 nm) substrate to act as an ultrasound receive element. The resonant frequency was ~ 6 MHz in water. The output end of an optical fiber, coupled to a pulsed laser diode (PLD), was fitted with a 2.5 mm ferrule. The PMUT ring array was concentrically mounted on the ferrule to obtain a miniaturized endoscopic PAI device. The observed photoacoustic bandwidth was ~75%, and a strong photoacoustic signal of ~13 mV peak-to-peak output was observed from a light absorbing target kept 5 mm away from the PMUT array. 2D and 3D photoacoustic images of the targets were obtained via raster scanning of the phantom sample. In the future, the functionality of the PMUT ring array will be enhanced through multichannel acquisition to obtain variable acoustic focus and limited view photoacoustic images in real time.

Item Type: Conference Paper
Publication: Progress in Biomedical Optics and Imaging - Proceedings of SPIE
Publisher: SPIE
Additional Information: The copyright for this article belongs to SPIE.
Keywords: Aluminum nitride; Endoscopy; III-V semiconductors; Image enhancement; Light; MEMS; Natural frequencies; Optical fiber fabrication; Optical fibers; Photons; Piezoelectricity; Transducers; Ultrasonic transducers; Ultrasonics, Micro-machined; Micromachined ultrasound transducers; Multi-channel acquisition; Photo-acoustic imaging; Photoacoustic signals; Piezoelectric; Piezoelectric layers; PMUTs, Nitrogen compounds
Department/Centre: Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited: 22 Nov 2022 09:53
Last Modified: 22 Nov 2022 09:53
URI: https://eprints.iisc.ac.in/id/eprint/77968

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