Structure formation on the surface of indium phosphide irradiated by femtosecond laser pulses

Abstract

Laser-induced periodic surface structures (LIPSS; ripples) with different spatial characteristics have been observed after irradiation of single-crystalline indium phosphide ͑c-InP͒ with multiple linearly polarized femtosecond pulses (130 fs, 800 nm) in air. With an increasing number of pulses per spot, N, up to 100, a characteristic evolution of two different types of ripples has been observed, i.e., (i) the growth of a grating perpendicular to the polarization vector consisting of nearly wavelength-sized periodic lines and (ii), in a specific pulse number regime ͑N =5-30͒, the additional formation of equally oriented ripples with a spatial period close to half of the laser wavelength. For pulse numbers higher than 50, the formation of micrometer-spaced grooves has been found, which are oriented perpendicular to the ripples. These topographical surface alterations are discussed in the frame of existing LIPSS theories.

Laser-induced periodic surface structures: Fingerprints of light localization

“…26 Two origins are not addressed in this article: the grating-assisted SPP mechanism mentioned above 24 and the change in the local angle of incidence. 8 The grating-assisted SPP mechanism is beyond the scope of this article because it involves a metallic state Re(ñ * ) < Im(ñ * ) of the material as well as interpulse feedback mechanisms. The change in the local angle of incidence is not considered, since this study is performed at normal incidence of the laser light.…”

“…Ripples which are either orthogonal [7][8][9][10][11][12][13][14][15] or parallel [16][17][18][19] to the polarization, with a periodicity significantly smaller than the laser light, have been observed for laser pulse durations in the picosecond and femtosecond regime. These are often referred to as high spatial frequency LIPSSs (HSFLs), and as for LSFLs, they were observed on metals, 18,20 semiconductors, [7][8][9][10][11][12]16,17 and dielectrics as well. [13][14][15]19 The influence of polarization, angle of incidence, and wavelength of a laser beam on LSFL formation strongly indicates that the phenomenon is mainly governed by the electromagnetic field.…”

“…The origin of HSFL is still under debate and several theories have been proposed to explain their formation, such as self-organization, 13,16 second-harmonic generation, 7,8,12 or the η theory extended with a modification of the optical properties. 12,19,23 It must be noted that the η theory was created to explain LIPSS formation at a time when HSFLs had not yet been observed.…”

Coherent linking of periodic nano-ripples on a ZnO crystal surface induced by femtosecond laser pulses

“…Various explanations have been offered for the development of periodic structures depending on the experimental conditions [13][14][15][16]. In many cases, the period of the observed surface structure is close to the wavelength of the incident radiation, i.e.…”

“…General methods to form micro-/nanostructures mainly focused on electron-beam lithography [5], nanoprint lithography [6], or chemical methods [7][8][9]. Recently, high spatial frequency laser induced periodic surface structures (HSFL) have been obtained following solid target irradiation with ultrashort laser pulses [10][11][12][13][14][15][16][17]. In many cases, however, the obtained nanostructures are either not well-patterned or not clearly long-range ordered.…”