The present invention relates to a subsurface laser-induced optical breakdown (LIOB) ablation system including an optical source for providing optical pulses and an optical waveguide for guiding the optical pulses to a subsurface target biological tissue site. The system is characterised in that it further includes a pulse shaping system configured to modify a temporal profile or a wavefront profile of an optical pulse provided by the optical source to compensate for temporal or spatial modifications imposed on the optical pulse during the passage of the optical pulse to the subsurface target biological tissue site, and configured to provide the compensated optical pulse to the optical waveguide for guidance to the subsurface target biological tissue site. The present invention also relates to a catheter and a subsurface laser-induced optical breakdown (LIOB) ablation method.