Prebreakdown energy absorption from intense laser pulses at 532 nm in NaCl

Four-photon absorption cross-section measurements in UV fused silica at 473 nm

With the use of I- and z-scan techniques, the four-photon absorption cross section in a UV fused silica sample has been measured to be σ₄=(1.0±0.5)×10^-115  cm⁸ s³ at 473 nm. This value is more than an order of magnitude lower than that known for other optical materials (KBr, KI, NaCl, TeO₂, and GeS₂).

Surface charging and impulsive ion ejection during ultrashort pulsed laser ablation

We report time-resolved studies using femtosecond laser pulses, accompanied by model calculations, that illuminate the difference in the dynamics of ultrashort pulsed laser ablation of different materials. Dielectrics are strongly charged at the surface on the femtosecond time scale and undergo an impulsive Coulomb explosion. This is not seen from metals and semiconductors where the surface charge is effectively quenched.