Nonlinear photoacoustic microscopy (PAM) is a novel approach to enhance contrast and resolution. In this study, a low-cost infrared (IR) lamp as a simple approach for nonlinear PAM is demonstrated. Numerical simulations are first performed to verify the nonlinear photoacoustic effect under steady heating for two cases: (a) Differentiation of absorbers with different Grüneisen coefficients; (b) enhancement of photoacoustic amplitude. Then, sets of experiments are conducted to experimentally demonstrate our proposed approach: (a) Longitudinal monitoring of photoacoustic A-line signals from two samples, porcine tissue ex vivo and hemoglobin and indocyanine green (ICG) solutions in tubes in vitro for demonstrating the above-mentioned two cases; (b) PAM imaging of hemoglobin and ICG solutions in tubes before and after IR lamp heating. Different signal change and amplitude enhancement are observed in different demonstrations, showing the efficacy of the proposed approach. By virtue of cost-effectiveness and decent performance, our work facilitates nonlinear PAM studies.
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http://dx.doi.org/10.1002/jbio.202100301 | DOI Listing |
Neurophotonics
October 2024
Technical University of Denmark, DTU Electro, Lyngby, Denmark.
Significance: Extending the photoacoustic microscopy (PAM) into the mid-infrared (MIR) molecular fingerprint region constitutes a promising route toward label-free imaging of biological molecular structures. Realizing this objective requires a high-energy nanosecond MIR laser source. However, existing MIR laser technologies are limited to either low pulse energy or free-space structure that is sensitive to environmental conditions.
View Article and Find Full Text PDFInverse Probl
December 2024
Oden Institute for Computational Engineering and Sciences, The University of Texas, Austin, TX 78712, United States of America.
Anal Chem
October 2024
Department of Precision Instruments, State Key Laboratory of Precision Measurement Technology and Instruments, Tsinghua University, Beijing 100084, China.
To overcome the light power fluctuation and frequency mismatch in photoacoustic spectroscopy (PAS), we proposed a self-corrected 1-only resonant cell-based PAS (1-RCPAS) gas analyzer. Based on the theoretical analysis of the 1 signal, a signal processing algorithm considering laser power-current nonlinearity is proposed. The 1-only algorithm is well-tailored for the resonant systems, requiring no time-division multiplexing.
View Article and Find Full Text PDFPhotoacoustics
October 2024
Taizhou Hospital, Zhejiang University, Taizhou, China.
Hydrocarbon gas sensing is a challenging task using laser absorption spectroscopy due to the complex and broad structure of absorption lines. This application requires quick, accurate and highly sensitive detection of hydrocarbon gases concentrations. In this paper, a compact photoacoustic spectrophone was developed to simultaneously measure methane, propane and isobutane.
View Article and Find Full Text PDFUltrasonics
December 2024
Institute of Biomedical Engineering & Technology, Academy for Engineering and Technology, Fudan University, Shanghai 200433, China; Department of Biomedical Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, China. Electronic address:
Osteoporosis is a systemic disease with a high incidence in the elderly and seriously affects the quality of life of patients. Photoacoustic (PA) technology, which combines the advantages of light and ultrasound, can provide information about the physiological structure and chemical information of biological tissues in a non-invasive and non-radiative way. Due to the complex structural characteristics of bone tissue, PA signals generated by bone tissue are non-stationary and nonlinear.
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