Superbroadening inH2O andD2O by self-focused picosecond pulses

Abstract

The dielectric breakdown intensity threshold, the critical power for self-focusing, and the power threshold for the production of spectral superbroadening have been measured in H, O and D20. For bandwidth limited pulses of 30 psec duration at 1.06 p,m, and 21 psec duration at 0.53 p,m, the superbroadening in water always required power levels sufficient for catastrophic self-focusing and intensities equal to the electric breakdown threshold.

Ultrafast supercontinuum generation in bulk condensed media

“…Alongside fused silica, in many occasions water serves as a prototypical nonlinear medium for studies of ultrafast light-matter interactions. Systematic studies of the spectral broadening in water date back to the mid-1980s [171] and successfully continue in the femtosecond laser era, see [11,[172][173][174] for the early accounts on femtosecond SC generation in water and some other liquids.…”

Scalable Shared Memory Supercomputer Replacement for DOD Research

“…reached by the collapsing pulse, and also limits the maximum rate of plasma generation 8 tp c I with p the plasma density and K the order of the MPI. The standard scenario [23,[40][41][42][43] maintains that the dominant contribution to spectral broadening comes from the spectral blueshifting due to the plasma [42,44], with the maximum blue-side frequency shift Awmax cx Otp cc I~a* Thus, according to the standard scenario, limiting of the maximum intensity Imax as self-focusing is arrested is the dominant factor that determines the spectral extent AWmax of SC generation.…”

Theoretical investigation of noncollinear phase-matched parametric four-photon amplification of ultrashort light pulses in isotropic media

“…The parametric gain factor /3 0 increases linearly with the effective pump pulbe intensity (/i/2) 1//2 . But there is an upper intensity limit 7 dth set by material damage in solids [55] and dielectric breakdown in liquids [56]. At high pump pulse intensities and long sample lengths, self-focusing may occur, which increases the laser intensity in an uncontrolled way.…”

“…/d,th(^0 = ^d,th(^SH) is assumed. Data are taken from [57] for the Schott glass SF10, from [58,59] for fused silica, and from [56] for D 2 0. An inverse square root dependence of 7 dth on pulse duration Af is assumed, i.e.…”

“…It should be noted that media with a large figure of merit for parametric four-photon amplification (small Xn\ responsible for self-phase modulation, small dispersion characterized by large Abbe number, high damage threshold intensity) and low Raman gain factor are widely used for picosecond and femtosecond light continuum generation (H 2 0 [11,12,56,72], D 2 0 [11,12,15,56], mixtures of H 2 0 and D 2 0 [73], ethylene glycol [74,75], mixtures of ethylene glycol and glycerin [76], fused silica [11,12], optical silica fibres [10,11,13,14,77], NaCl crystal [12], compressed xenon gas [78,79], compressed nitrogen gas [78,79]). …”