A method and apparatus, of providing endovascular therapy. The steps include arranging optical fibers within a catheter, the catheter having a tip whose length is at least 1 cm and whose diameter of less than 1 millimeter, connecting an excimer laser to the optical fibers; and delivering laser energy from the excimer laser in excess of a fluence of 60-mJ/mm2 at 40 Hertz through the optical fibers. The delivering of the laser energy may be to non-calcified or calcified deposits of an atherosclerotic lesion to ablate the same. The method also includes the step of inserting the catheter through an artery by pushing the same until the tip is in within laser energy striking distance of the atherosclerotic lesion.