A novel method for non-contact and continuous detection of photoacoustic signals is presented and experimentally demonstrated. The approach is based on analysis of the contrast of time-varying speckle patterns, and suggests a more robust alternative in respect to interferometric and refractometric available solutions.
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http://dx.doi.org/10.1364/OL.44.003110 | DOI Listing |
Micromachines (Basel)
November 2024
Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China.
Photoacoustic imaging has emerged as a promising modality for medical imaging since its introduction. Photoacoustic microscopy (PAM), which is based on the photoacoustic effect, combines the advantages of both optical and acoustic imaging modalities. PAM facilitates high-sensitivity, high-resolution, non-contact, and non-invasive imaging by employing optical absorption as its primary contrast mechanism.
View Article and Find Full Text PDFDiscriminative internal imaging for different chip layers can pinpoint the location of critical defect in the flip chips, yet existing methods face challenges in in-line imaging to identify defects or structures from the sub-surface within the silicon substrate and their underlying coating. To address these challenges, we develop and verify layered elasto-optic models for photoacoustic remote sensing microscopy (PARS) that distinguish structures from multi-layers within a single device for in-line flip-chip wafer inspection. A finite-difference time-domain algorithm based on transparent source (TS-FDTD) accurately predicts different initial slopes of PARS signals within the silicon-metal and the silicon-air models.
View Article and Find Full Text PDFSci Rep
October 2024
Photonics Research Group, Ghent University-IMEC, Technologiepark-Zwijnaarde 126, 9052, Ghent, Belgium.
Photoacoustic imaging has emerged as a powerful, non-invasive modality for various biomedical applications. Conventional photoacoustic systems require contact-based ultrasound detection and expensive, bulky high-power lasers for the excitation. The use of contact-based detectors involves the risk of contamination, which is undesirable for most biomedical applications.
View Article and Find Full Text PDFPhotoacoustic (PA) remote sensing (PARS) microscopy represents a significant advancement by eliminating the need for traditional acoustic coupling media in PA microscopy (PAM), thereby broadening its potential applications. However, current PARS microscopy setups predominantly rely on free-space optical components, which can be cumbersome to implement and limit the scope of imaging applications. In this study, we develop an all-fiber miniature non-contact PA probe based on PARS microscopy, utilizing a 532-nm excitation wavelength, and showcase its effectiveness in in vivo vascular imaging.
View Article and Find Full Text PDFAdv Sci (Weinh)
October 2024
Department of Nanoengineering, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA.
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