We introduce azobenzene-functionalized polyelectrolyte multilayers as efficient, inexpensive optoacoustic transducers for hyper-sound strain waves in the GHz range. By picosecond transient reflectivity measurements we study the creation of nanoscale strain waves, their reflection from interfaces, damping by scattering from nanoparticles and propagation in soft and hard adjacent materials like polymer layers, quartz and mica. The amplitude of the generated strain ε∼ 5 × 10(-4) is calibrated by ultrafast X-ray diffraction.
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http://dx.doi.org/10.1039/c6nr01448h | DOI Listing |
Ultrasonics
December 2024
Universidad Carlos III de Madrid, Avenida de la Universidad, 30, Leganes, Madrid, Spain.
The most common transducers used to generate ultrasound in medical applications are based on short electrical pulses applied to piezoelectric transducers and capacitive micromachined ultrasound transducers. However, piezoelectric transducers have a limited frequency bandwidth, defined by their physical thickness, and capacitive micromachined ultrasound transducers have poor transmission efficiency. The high frequency cutoff limits the spatial resolution of ultrasonic images.
View Article and Find Full Text PDFPhotoacoustics
December 2024
Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Zurich CH-8057, Switzerland.
Optoacoustic (OA) tomography is a powerful noninvasive preclinical imaging tool enabling high resolution whole-body visualization of biodistribution and dynamics of molecular agents. The technique yet lacks endogenous soft-tissue contrast, which often hampers anatomical navigation. Herein, we devise spiral volumetric optoacoustic and ultrasound (SVOPUS) tomography for concurrent OA and pulse-echo ultrasound (US) imaging of whole mice.
View Article and Find Full Text PDFAcad Radiol
October 2024
Associate Professor, Breast Imaging and Intervention, Dept. Of Radiology, University of Texas Health Sciences Center of San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900. Electronic address:
Rationale And Objectives: The combination of functional biologic data and imaging appearance has the potential to add diagnostic information to help the radiologist evaluate breast masses in an efficient, effective, and cost-conscious manner. This is the first clinical evaluation of the Gen 2(Model 9100, 8101) Imagio® System to assess image quality with both the stand-alone internal ultrasound (IUS), ultrasound-only transducer, and the Optoacoustic/Ultrasound (OA/US) duplex probe (1,2). This study assesses palpable and non-palpable breast abnormalities in patients who are referred for diagnostic breast ultrasound work-up.
View Article and Find Full Text PDFNat Commun
August 2024
Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, Germany.
Fiber-based interferometers receive significant interest as they lead to miniaturization of optoacoustic and ultrasound detectors without the quadratic loss of sensitivity common to piezoelectric elements. Nevertheless, in contrast to piezoelectric crystals, current fiber-based ultrasound detectors operate with narrow ultrasound bandwidth which limits the application range and spatial resolution achieved in imaging implementations. We port the concept of silicon waveguide etalon detection to optical fibers using a sub-acoustic reflection terminator to a Bragg grating embedded etalon resonator (EER), uniquely implementing direct and forward-looking access to incoming ultrasound waves.
View Article and Find Full Text PDFUltrasonics
August 2024
School of Integrated Circuit, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China; State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai 200050, China. Electronic address:
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