A method that uses an integrating sphere as a platform for photoacoustic measurement of the Grüneisen parameter Γ of absorbing liquids is developed. Derivation of a simple equation for determining Γ is presented. This equation only requires the voltage peak-to-peak value of the photoacoustic signal detected by a flat transducer and the relative energy of the incident light measured by a photodetector. Absolute detector sensitivities are not required. However, a calibration procedure is necessary. An experimental setup is constructed in order to implement and verify the method. Aqueous ink solutions are used as absorbing liquids to determine the calibration (instrument) constants. Validation of the equation is done by determining Γ of ethanol at room temperature. The obtained value of Γ(ethanol) = 0.72 ± 0.06 has a 7% relative difference to the calculated value from known thermal properties reported in literature.
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http://dx.doi.org/10.1063/1.4890666 | DOI Listing |
Sensitive detection of incident acoustic waves over a broad frequency band offers a faithful representation of photoacoustic pressure transients of biological microstructures. Here, we propose a plasmon waveguide resonance sensor for responding to the photoacoustic impulses. By sequentially depositing Au, MgF, and SiO films on a coverslip, a composite waveguide layer produces a tightly confined optical evanescent field at the SiO-water interface with extremely strong electric field intensity, enabling the retrieval of photoacoustic signals with an estimated noise-equivalent-pressure (NEP) sensitivity of ∼92 Pa and a -6-dB bandwidth of ∼208 MHz.
View Article and Find Full Text PDFPhotoacoustics
October 2024
Wuhan National Laboratory for Optoelectronics (WNLO) and National Engineering Research Center of Next Generation Internet Access-system, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China.
A proof-of-concept on-beam tuning-fork-enhanced photoacoustic sensor based on an open-closed single-tube acoustic-microresonator (AmR) was proposed and investigated for the first time, to the best of our knowledge. Due to the high acoustic amplification effect, the open-closed AmR improved the detection sensitivity by 54 times with respect to the bare tuning fork (TF). Compared to traditional dual-tube/single-tube on-beam spectrophone configuration, the developed approach significantly facilitates the laser beam alignment and reduces the sensor size and gas consumption.
View Article and Find Full Text PDFPhotoacoustics
February 2025
Department of Biomedical Engineering, Tufts University, Medford, MA, United States.
Depth-dependent fluence-compensation in photoacoustic (PA) imaging is paramount for accurate quantification of chromophores from deep tissues. Here we present a user-friendly toolkit named PHANTOM (PHotoacoustic ANnotation TOolkit for MATLAB) that includes a graphical interface and assists in the segmentation of ultrasound-guided PA images. We modelled the light source configuration with Monte Carlo eXtreme and utilized 3D segmented tissues from ultrasound to generate fluence maps to depth compensate PA images.
View Article and Find Full Text PDFSensors (Basel)
November 2024
Dipartimento di Scienze e Tecnologie Agrarie, Alimentari Ambientali e Forestali, Laboratorio di Patologia Vegetale Molecolare, Università degli Studi di Firenze, Via della Lastruccia 10, 50019 Sesto Fiorentino, Italy.
Seed-borne pathogens pose a significant threat to global food security. This study focuses on pv. (), a quarantine plant pathogen causing bacterial wilt of common beans.
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November 2024
The Artificial Intelligence Research Center, Novosibirsk State University, Pirogova Str. 2, 630090 Novosibirsk, Russia.
In this study, we address the challenge of estimating the resonance frequency of a photoacoustic detector (PAD) gas cell under varying temperature conditions, which is crucial for improving the accuracy of gas concentration measurements. We introduce a novel approach that uses a long short-term memory network and a self-attention mechanism to model resonance frequency shifts based on temperature data. To investigate the impact of the gas mixture temperature on the resonance frequency, we modified the PAD to include an internal temperature sensor.
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