Variable-azimuth laser ablation: principles and application for film deposition on long tubes and tapes

A new development of the pulsed laser ablation (PLA) technique based on var iable azimuth ablation (VAA) is reported. The VAA itself is based on period ic variations of the azimuth of the laser beam relative to the target at a constant angle of beam incidence. Such variations result in a suppression o f cone-valley surface structures which tend to develop in the case of a fix ed azimuth. VAA leads to high-level stabilization of the laser plume during a long-term deposition process. As a result, the VAA method stabilizes the deposition rate with a tolerance of only 3%-6% instead of a 90% decrease i n the rate as in conventional PLA. Different possibilities for the realizat ion of the VAA technique based on 2- and 3-way target scans are discussed. In the case of large areas, VAA technique with a meander beam target scan i s capable of the deposition of high-quality multicompositional superconduct ing films on tubes and tapes more than 1 m in length.