Ultrashort excitations of surface polaritons and waveguide modes in semiconductors

Rippled area formed by surface plasmon polaritons upon femtosecond laser double-pulse irradiation of silicon: the role of carrier generation and relaxation processes

“…Their orientation is perpendicular to the laser beam polarization and the periods typically range between ∼ 0.6λ and λ , depending on the degree of material excitation [10,12], and the number of laser pulses per spot [11]. Several authors have suggested that these structures are caused by excitation of surface plasmon polaritons (SPP) at the air -silicon interface when the material turns from a semiconducting into a metallic state [2,10,13]. The interference between the electromagnetic field of the SPP and the incident laser pulse leads to a spatially modulated deposition of optical energy to the electronic system of the material.…”

Femtosecond laser-induced periodic surface structures

“…15,17,18 High-spatial-frequency LIPSS (HSFL) with spatial periods significantly smaller than the irradiation wavelength (K HSFL < k=2) have been observed predominantly for transparent materials and with orientations often perpendicular 15,17 and sometimes parallel 14,19 to the polarization. The origin of the HSFL is controversially discussed in the literature where different mechanisms such as second-harmonic generation, 5,15 the involvement of specific types of plasmon modes, 20 or self-organization have been proposed. 16 Table I provides a literature survey on the spatial periods of LSFL and HSFL as well as their orientation with respect to the laser beam polarization for representative inorganic solids-ordered according to their optical band gap energies-upon irradiation with Ti:sapphire fs-laser pulses (k $ 740-800 nm, s ¼ 25-160 fs, and repetition rate 5 kHz) in air or in vacuum under nearly normal incidence.…”

Growth of ZnO nanostructures by femtosecond laser irradiation of polycrystalline targets

“…The subsequent work by Sipe and coworkers [6,7] provided the initial basis for the comprehension of their formation mechanism. These periodic structures occur in all types of materials [8] and the details regarding their formation mechanism with respect to the specific material, and processing conditions are still a very active field of research [1,[9][10][11][12][13][14][15][16][17][18][19]. Two different kinds of LIPSS are usually observed in most materials: low and high spatial frequency LIPSS (LSFL and HSFL, respectively), with periods K of the order of the incident wavelength for LSFL or much smaller, typically K/4-K/6, for the HSFL.…”