Abstract

Laser polishing of thin YBaCuO films has been observed for the first time. It was established that the threshold for laser ablation of HTSC films depends on the their thickness. The processing of films with an excimer laser at a certain level below the threshold can significantly reduce the surface roughness. Measurements of the optical properties of YBaCuO films before and after the laser treatment, combined with a subsequent annealing in an oxygen atmosphere, revealed that the modification of the thin films by the excimer laser can be either reversible or irreversible. An explanation for the observed effect is presented on the basis of the analysis of the various ablation mechanisms of HTSC. The novel low-energy ablation mechanism is studied. That mechanism is connected with the macroparticles ejection due to the pressure oscillation of oxygen liberated in the course of the laser-assisted HTSC thermodecomposition. The theoretical model for the calculation of macroparticle size and velocity is developed.

© 1994 IEEE