The pulsed laser deposition of YBa2Cu3O7−x targets by excimer laser at fluences of 4–10 J cm−2 in low pressure oxygen backgrounds yields emissive plumes with kinetic energies of 50–200 eV, driving the formation of a shock front with Mach numbers of M = 10–50. The propagation of the shock front is independent of atomic species and adequately characterized by the Sedov–Taylor shock model if the dimensionality of the plume is allowed to deviate from ideal spherical expansion. The ideal efficiency of energy conversion from laser pulse to shock expansion is nearly unity at 1 Torr, but decreases rapidly at lower pressures, where the plume expands beyond the laser footprint during ablation. The low oxygen background pressures, 100–1000 mTorr, typically employed for the production of superconducting films is sufficient for the generation of a strong shock front with shock thickness of 5 mm to less than 0.4 mm, but too low to develop three-dimensional flow. Indeed, dimensionality of the expansion ranges from n = 0.8 to 2.4 over the background oxygen pressure range of 25–1000 mTorr. Shock strength is proportional to the Mach number and inversely dependent on pressure, indicating a thickness limited to approximately the collision mean free path.

Emission time-of-flight (TOF) profiles have been obtained using gated imagery to further the process control during the pulsed laser deposition of the high temperature superconductor, YBa2Cu3O7−x. An intensified charge coupled device array was used to obtain a sequence of plume images at 10ns temporal resolution and 0.2mm spatial resolution. Plume imagery is transformed to TOF profiles and pulse-to-pulse variations removed using physically based smoothing techniques. Comparison with non-imaging sensors establishes excellent agreement, with systematic uncertainties in streaming speed and temperatures of less than 15% and 8%, respectively. The resulting streaming speeds of 0.4–1.2×106cm∕s and characteristic temperatures of 20000–200000K are characterized across the full plume. This new imaging TOF technique enables the monitoring of the complete evolution of speed distributions. Indeed, significant deviations from the forward-directed Maxwellian speed distributions are observed.

The surface of laser‐treated ceramic hard disk drive head sliders has been imaged with the atomic force microscope (AFM) and ultrasonic force microscope (UFM). The surface topography image from the AFM is compared with the elasticity image generated by the UFM on the same region. Images of the surface structure changes along with microcracking in the laser‐treated regions are presented. The possible reasons for the development of microcracking and the enhanced contrast that the UFM provides of the microcracks and the material microstructure changes in the laser‐treated region are discussed.

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