Precision measurement of optical signal power is provided. The method includes producing a control signal to the turbocharger. The dual lumen catheter provides the advantage that the radiation source wire does not contact body tissue thereby eliminating the need for sterilization of the wire for reuse. By controlling the degree of overlap between the stripe and the connectors the conductance of heat from the stripe into the connectors can be varied, thereby allowing control of the manner in which the fuse blows when irradiated. The method is also useful for polishing dielectric silicon-containing substrates at a high rate relative to semiconductor silicon-containing substrates.