KNN-based single crystal high frequency transducer for intravascular photoacoustic imaging
Abstract
With its thickness decreasing down to 60 μm, the (K <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.45</sub> Na <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.55</sub> ) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.96</sub> Li <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.04</sub> NbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (KNLN) single crystals maintains superior piezoelectric constant (d <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">33</sub> = 675 pC N <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> ). In combination with a 200 μm core multimode fiber, the successful fabrication of a tiny intravascular photoacoustic probe with a 1 mm outside diameter is achieved. The intravascular photoacoustic imaging of the atherosclerotic lesion of a human artery is presented. In the time-domain and frequency-domain images, calcified regions are clearly distinguishable from surrounding tissue. These interesting results demonstrate that KNN-based lead-free piezoelectric single crystals are a promising candidate to substitute for lead-based piezoelectric materials for photoacoustic imaging in the future.