Abstract: An improved laser heated intravascular cautery cap construction includes a generally cylindrical outersidewall, and a tappered, annular, distal end wall joining the two sidewalls and defining a closed annular space therebetween. A bore extending axially through the inner sidewall is dimentioned to receive in freely sliding fashion an arterial guidewire or other device such as a doppler flow sensor or an optical bundle for viewing. A unitary or multi-segment annular target element is received within the distal portion of the annular space, and is secured to the outer sidewall adjacent to the end wall with a gap defined between the target element and the inner sidewall. A plurality of holes extend through a connector member parallel to the axis of the sidewalls, each hole receiving therethrough one of a plurality of optical fibers extending through the arterial catheter to a laser light source.