Ashing of an organic film from a substrate is carried out by providing a plasma comprising a gas or gas mixture selected from the following groups: sulfur trioxide alone; sulfur trioxide plus one supplemental gas; and sulfur trioxide plus at least two supplemental gases. An example medical device may include a catheter shaft. The control unit is operable to control the fluid delivery system. It consists essentially of: 2 weight percent to 95 weight percent Psoralea; 2 weight percent to 95 weight percent Scutellaria; and 2 weight percent to 95 weight percent Xanthium. The shape of the adjusted adaptive optic can be determined with the aberration sensor by transmitting an adaptive optic configuration measurement beam along the optical path.