Balloon surface photoacoustic pressure wave generation to disrupt vascular lesions

A photoacoustic catheter adapted for placement within a blood vessel having a vessel wall includes an elongate shaft, a balloon and a photoacoustic transducer. The elongate shaft can extend from a proximal region to a distal region. The elongate shaft can include a light guide that is configured to be placed in optical communication with a light source. The balloon is coupled to the elongate shaft, and can be configured to expand from a collapsed configuration suitable for advancing the photoacoustic catheter through a patient's vasculature to a first expanded configuration suitable for anchoring the photoacoustic catheter in position relative to a treatment site. The photoacoustic transducer can be disposed on a surface of the balloon and in optical communication with the light guide. The photoacoustic transducer can include a light-absorbing material and a thermal expansion material.