Time-resolved optical microscopy of a laser-based forward transfer process

Matrix-assisted pulsed laser evaporation direct write was investigated by ultrahigh speed optical microscopy. A composite barium-zirconium titanate/alpha -terpineol layer was irradiated by 355 nm laser pulses with a 150 ns pulse width, and it was observed that material removal does not begin until after the end of the pulse (t > 200 ns) and continues for 1 mus after the irradiation. The desorption plume consists of micron-size particles moving with a velocity of similar to0.2 km/s. The slow response is attributed to the combination of particle absorbers and highly viscous fluid. The ability to form continuous, pinhole-free coatings is due to slow coalescence of the particles. (C) 2001 American Institute of Physics.