BRIEF INTENSE LASER FIELDS IN BULK MATTER

The intense fields in laser pulses produce a wide variety of nonpertur bative and nonlinear effects within individual atoms or molecules (e.g ., harmonic generation, multiphoton ionization, etc.). Aggregates of a toms (e.g., vapors, clusters, metals, glass, etc.) subject to intense pulses exhibit a variety of breakdown (or damage) phenomena that deriv e from the strong-field effects in individual atoms and the collective effect of bulk matter. We review some of these connections, with part icular emphasis on recent investigations in our laboratory of short-pu lse laser-induced changes to transparent dielectric solids. Although t he phenomena of laser-induced breakdown and damage have great complexi ty in general and requires elaborate details ranging from electron col lision physics to strength of materials and fracture, simplifications become possible for short pulses. In particular, the brevity of the la ser pulse implies that the threshold for material damage is primarily determined by conduction electrons. We comment on the implications of the simplifying physics that becomes applicable for short pulses, and the consequences of this simplification both for theoretical modeling and for useful applications.