KNN-based single crystal high frequency transducer for intravascular photoacoustic imaging

With its thickness decreasing down to 60 μm, the (K
_0.45
Na
_0.55
)
_0.96
Li
_0.04
NbO
₃
(KNLN) single crystals maintains superior piezoelectric constant (d
₃₃
= 675 pC N
^-1
). 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.