Intrinsic single- and multiple-pulse laser-induced damage in silicate glasses in the femtosecond-to-nanosecond region

Abstract

We show that the threshold power density of the intrinsic laser-induced damage in borosilicate glass at ϳ1 m wavelength does not depend on pulse duration from 2 ϫ 10 −13 to 3 ϫ 10 −8 s and has the same value for both single-and multiple-pulse exposure of the sample. This indicates that the mechanism of the intrinsic damage in glasses involves a collective response of a certain volume in the dielectric as a whole, such as "dielectric-metal" phase transition, rather than a process of individual generation and accumulation of electrons, such as multiphoton, tunneling, or avalanche. Also, we demonstrate that under femtosecond exposure the threshold of the plasma formation in transparent glasses is considerably higher than the threshold of the residual change of medium parameters.

Glass formation in and structural investigation of Li2S+GeS2+GeO2 composition using Raman and IR spectroscopy

“…At high concentrations of Li 2 S (x P 0.5), a new band is observed at 780 cm À1 . Since the strong and broad m as (Ge-O-Ge) band appearing at 700-900 cm À1 and overlapping the m s (Ge-O À ) mode in the IR spectra [24] is not observed in the Raman spectra [14], this band can be assigned to the m s (Ge-O À ) of the non-bridging oxygen band from the peak assignment of the non-bridging oxygen band ($800 cm À1 ) in the alkali germinate glasses [22]. As expected from the depolymerizing role of Li 2 S, the bridging sulfur band observed at 354 cm À1 decreases in intensity over the entire composition range.…”

Three-Dimensional Micro- and Nano-Structuring of Materials by Tightly Focused Laser Radiation

“…For experimental detection of the breakdown by optical plasma emission, it appears as an instant step-like event. 113 This apparent instantaneous dielectric-to-metal transition was explained as analogous to the Mott transition: 113 an effective increase of outer electron orbitals due to strong electric light field causes a loss of correlation between the ions and electrons since the orbitals become overlapping. This randomization creates uncorrelated electrons at certain strength of E-field (irradiance) in a step-like fashion.…”

Interaction of ultrashort-laser pulses with induced undercritical plasmas in fused silica

“…While damage is a visible record of the pulse-plasma interaction, it is the initial interaction itself and resulting ultrafast free-electron generation that must be understood and controlled when using femtosecond pulses. * Numerous studies have included a postmortem analysis of the optical damage on the surface and in the bulk and used a wide variety of computer simulations to interpret the results [8,19,[22][23][24][25][26][27]. While those studies have greatly advanced the understanding of the induced-plasma processes and the nonlinear effects inside the material above the damage threshold, physical processes leading up to the damage regime are not accessible with many of these experimental techniques.…”