Generation of surface electromagnetic waves in semiconductors under the action of femtosecond laser pulses

The significant role of plasmonic effects in femtosecond laser‐induced grating fabrication on the nanoscale

“…In detail, the dielectric constant of the highly excited instantaneous state of the irradiated material can be described by the Drude model and mainly determined by the free electron density (, which is related to the excited level of the irradiated material and may be varied over a wide range for different regions of the ablated crater due to the variational irradiation fluence coming of the Guassian field distribution of laser beams. Actually, as demonstrated in previous studies , , , , , , , , the distribution of different kinds of gratings formed in a crater is strongly associated with the distribution of irradiation fluence, i.e. the distribution of .…”

“…Besides DSGs, lately ultrafast laser‐induced near‐subwavelength gratings (NSGs, generally ) have attracted renewed interest , , , , , , of researchers, because of the application prospects and the nonclassical subwavelength characteristics , , , , , suggesting new mechanisms related to the excitation of surface plasmons (SPs) , , , beyond the traditional picture (linked with the terms NSG and DSG, for the different types of laser‐induced periodic surface structures (LIPSSs), alternative terms LSFL (low spatial frequency LIPSS) and HSFL (high spatial frequency LIPSS) are widely used in the literature; note that NSG is used instead of LSFL for referring in particular to the “near‐subwavelength” LSFL, and accordingly DSG is used instead of HSFL). Based on the principles of plasmonics, a concise physical picture for the formation of NSGs has been proposed : NSGs result from the initial direct SP‐laser interference and the subsequent grating‐assisted SP‐laser coupling, i.e.…”

GeO2 Films with Ge-Nanoclusters in Layered Compositions: Structural Modifications with Laser Pulses

“…Martsinovsky et al (Martsinovsky et al, 2009) showed that, under the action of femtosecond laser pulses, intense photo-excitation of semiconductor surface, which dramatically modifies its optical response and provides conditions for generation of surface electromagnetic waves of various types, becomes possible. Martsinovsky et al have also discussed the interrelation of electronic processes optically induced in the near-surface layer with the formation of periodical surface microstructures that were observed in experiments on irradiation of silicon targets.…”

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

“…In the last decade, along with the application of ultrafast lasers in the field of laser ablation, the various structures induced by the lasers have attracted considerable interest from researchers, not just for the broad application prospects , but for the rich physics related to the phenomena . In particular, the distinct subwavelength characteristic of femtosecond (fs) laser‐induced structures , which deviates from the prediction of classical theories and suggests new underlying mechanisms of femtosecond laser–solid interaction, has received great attention . Remarkably, the sizes of the formed apertures can decrease to an astonishing 10‐nm scale , merely a few tenths of the laser wavelength (λ), implying new physics for laser‐induced damage at the ultradeep‐subwavelength scale.…”

“…Remarkably, the sizes of the formed apertures can decrease to an astonishing 10‐nm scale , merely a few tenths of the laser wavelength (λ), implying new physics for laser‐induced damage at the ultradeep‐subwavelength scale. Recently, it has been widely accepted that the origin of laser‐induced near‐subwavelength gratings (NSGs) is closely related to the interference between the incident laser and the surface‐bound electromagnetic (EM) wave , that is, surface plasmons (SPs) , and the following grating‐assisted SP–laser coupling . Further, the localized SPs excited in the grooves of laser‐induced deep‐subwavelength gratings (DSGs) can generate extraordinary field enhancement and thus act as an important positive feedback for the polarization‐dependent growth of the gratings .…”