Cumulative material damage from train of ultrafast infrared laser pulses

Abstract

We developed a systematic experimental method to demonstrate that damage threshold fluence (DTF) for fused silica changes with the number of femtosecond laser (800 nm, 65 ± 5 fs, 10 Hz and 600 Hz) pulses. Based on the experimental data, we were able to develop a model which indicates that the change in DTF varies with the number of shots logarithmically up to a critical value. Above this value, DTF approaches an asymptotic value. Both DTF for a single shot and the asymptotic value as well as the critical value where this happens, are extrinsic parameters dependent on the configuration (repetition rate, pressure and geometry near or at the surface). These measurements indicate that the power of this dependence is an intrinsic parameter independent of the configuration.

Self-induced birefringence of white-light continuum generated by interaction of focused femtosecond laser pulses with fused silica

“…Plasma then expands and increases the temperature and pressure in the vicinity of the initial breakdown region. The expansion of the plasma out of the central hot core is supposed to be the result of a strong shock wave front, and thermal conduction proceeds [21,22] . Thermal conduction from the damaged region into the surrounding pristine material enlarges the heated region, and thus expands the absorbing region.…”

Manipulation of Terahertz Wave Based on Three-Layer Transmissive Pancharatnam-Berry Phase Metasurface

“…It should be noted that all dielectric metasurface structures have been proposed in our previous paper [62], and the element structure of the proposed metasurface belongs to resonant type of metasurfaces [63,64]. This kind of resonance phase metasurface can move the resonance frequency through the change of structural parameters, and then change the phase of a certain frequency point, resulting in phase mutation.…”

Efficient carpet invisibility cloaking with dielectric resonant metasurfaces in terahertz region

“…Recently, metasurface has been proposed as a development version of metamaterials [9][10][11][12][13][14]. Metasurface can be applied in holography, absorber, metalens, bound-state in continuum, etc [15][16][17][18][19]. Specially, metasurface can be also used in invisible cloaking [11].…”