Spontaneous scaling down of femtosecond laser‐induced apertures towards the 10‐nanometer level: the excitation of quasistatic surface plasmons

Abstract

During ultrafast laser ablation on ZnO, the feature sizes of laser‐induced apertures always decrease spontaneously with the pulse increasing and the crater extending, and may eventually approach an astonishing 10‐nm scale, an ultradeep‐subwavelength laser–solid interaction regime relating new physics in laser‐induced damage. Based on the fundamental theories of plasmonics, it is proposed that the spontaneous scaling‐down originates in the conversion of physical regimes of plasmonic interaction from the optical regime to the electrostatic regime, which arouses quasistatic SPs with interaction scales far beyond the diffraction limit and results in ultrafast, nonthermal ablation for extraordinary electrostatic field enhancement. Basically, “nanoscale” eliminates electromagnetic retardation effects greatly, brings an instantaneous respond to the incident field, and arouses electrostatic interactions with giant local‐field enhancement, which may exert tremendous electrostatic forces on superficial electrons and ions and eventually lead to an “ultrafast” electrostatic nanoexplosion. Thus, the characteristics of simultaneous “nanoscale” and “ultrafast” arise spontaneously in femtosecond laser ablation.

All semiconductor enhanced high-harmonic generation from a single nanostructured cone

“…Two deep subwavelength cracks appear close to the center of the cone after half an hour of exposure (SEM-image in Fig. 4c) 31 . Due to the local field enhancement self-organized reshaping occurs which leads to a higher field enhancement than in the initial pristine cone.…”

Formation of nanogratings in a porous glass immersed in water by femtosecond laser irradiation

“…5(i)). These results establish an important link between the formation of volume nanograting in glass and surface nanoripples on various substrates observed previously, as the interface created in bulk glass can play the similar role for surface plasma wave excitation [23][24]. The above observation provides crucial guidance for theoretical modeling.…”

“…(1). In addition, similar to the excitation of surface plasma wave with femtosecond laser pulses [23,29], plasma waves can also be excited at the interface, as illustrated in Fig. 7(a).…”

Direct-write laser-induced self-organization and metallization beyond the focal volume in tellurite glass

“…Step 2: The first few pulses create an electric-field enhancement through the formation of surface plasmonpolariton pairs (SPPs) that initiate the formation of self-organized nanostructures within the focal volume [49,50]. For specific conditions, surface electromagnetic waves (SEWs) through surface plasmon-polariton coupling (SPPs) can be excited.…”