Laser-Generated Electron Emission from Surfaces: Effect of the Pulse Shape on Temperature and Transient Phenomena

摘要

Surface temperatures generated by gaussian, rectangular and triangular laser pulses are determined by solving a heat diffusion equation. The dependence of the temperature on the pulse shape, and in turn the dependence of the thermal diffusivity and absorbtance on the temperature, are investigated. The lifetime of an adspecies on a laser-heated solid e.g., Cs on W) is estimated in terms of the temperature, the desorption energy and the coverage. The mechanism of laser-generated electron emission from the adspecies is analyzed by means of the Richardson equation. A condition for generating an intense electron beam is that the laser pulse duration and the rise time of the temperature must be less than the lifetime of the adspecies. (Author)