Non reciprocal writing and chirality in femtosecond laser irradiated silica

Abstract

We ascertain by measuring the surface topography of a cleaved sample in which damage lines have been written in volume by scanning with a femtosecond laser, that matter shearing occur along the laser track with alternating sign (scissor or chiral effect). We note that the shearing in the head of the laser tracks change its sign with the change in scanning direction (pen effect or non reciprocal writing). We also show that nanostructures in the head are nano-shearing, with all the same sign whatever the direction of writing may be. We suggest that symmetries revealed by the shearing mimic the laser induced electron plasma density structures and inform on their unusual symmetries induced by the laser beam structures.

Nanograting Orientation Influence on Stress Induced by Femtosecond Laser in Fused Silica

“…These nanogratings form perpendicular to the electric field of the laser light [3]. Recently, we showed that the formation of nanogratings is also associated with a localized volume expansion [5], consistent with the hypothesis of porous material forming inside the laser affected volume [6].…”

A tutorial on optics for ultrafast laser materials processing: basic microprocessing system to beam shaping and advanced focusing methods

“…It has been found that the pulse-front tilt can induce the so-called ' quill writing ' effect in femtosecond laser processing, i.e., the laser-induced modifications in homogeneous materials show a remarkable change when the writing direction is reversed [18] . The microscopic mechanism underlying this effect has not yet been fully understood, whereas it seems to be closely linked to the structure existing in the electron plasma [18,49,50] . The ' quill writing ' effect opens new opportunities for controlling nano-texture formation in processed materials, which has important consequences on various applications such as the writing of waveguides and polarization-sensitive devices, and the fabrication of microfluidic channels.…”

Time-resolved plasma measurements in Ge-doped silica exposed to infrared femtosecond laser

“…Indeed, in the MPI regime, the rate is σ k I k ρ at , where σ k is the MPA coefficient for absorption of k photons and ρ at is the density at the top of the VB: i.e., 2.2 × 10 22 /cm 3 and N tr ∼ σ I N 0 . The number of photons required is determined by the smallest k, which satisfies the relation k.hω > E g (forbidden gap of the dielectrics).…”

“…Today advanced femtosecond laser systems offer a myriad of material interactions in silica-based glasses, from surface machining, to annealing, forming, and refractive index changes (isotropic or anisotropic) writing. 1,2 Recently, other properties have also arisen, including chirality, 3,4 directional dependent writing, [3][4][5][6] glass decomposition, 7 nanocluster precipitation and shaping, 8 and elemental distribution with a subwavelength resolution. 7,9 No other technique has the potential to realize 3D multicomponent photonic devices fabricated in one single step within a variety of transparent materials.…”