Femtosecond laser-induced periodic structure writing on diamond crystals and microclusters

Abstract

Three-dimensional (3D), periodic nanowriting on diamond clusters is reported in this letter. Concentric circular rings were observed on diamond microclusters, nucleated near the periphery of a laser-irradiated region, when chemical-vapor deposited diamond was processed in air, with laser pulses of 380 fs duration and at a wavelength of 248 nm. Periodic ripples also have been observed on single-crystal and polycrystalline diamond surfaces. Further, it is experimentally shown that the periodicity of these corrugated two-dimensional and 3D structures is shorter than that of the laser wavelength used (248 nm for the excimer fs laser and 825 nm for the Ti–sapphire fs laser).

Two-photon polarization-selective etching of emergent nano-structures on diamond surfaces

“…The rich variety of patterns produced as functions of facet and polarization reveal that the ejection probability is a complex function of the local surface structure and beam polarization. Such an ejection mechanism is consistent with the thresholdless and 'cold' nature of the process, and is distinct from the exponential and thermal nature of the periodic structuring observed previously [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] when using higher intensities, either near or above the ablation threshold. Further work is needed to determine whether bond scission results from direct coupling of the ultraviolet with carbon-carbon bonds or is reliant on cooperative processes with electronic states associated with surface reconstructions, radical sites or chemisorbed atoms.…”

“…The observed patterning has starkly contrasting properties to the laser-induced periodic surface structuring observed, to date, in any material [20][21][22][23][24][25][26][27] including diamond 20,[28][29][30][31] . For incident intensities near the ablation threshold or at the fringes of an ablation spot, ripple-like structures are produced with periodicity approximately equal to the wavelength of the incident light and with direction perpendicular to the laser polarization, except in a few special cases that combine angle of incidence and polarization to perturb the pattern symmetry 25,27 .…”

“…For incident intensities near the ablation threshold or at the fringes of an ablation spot, ripple-like structures are produced with periodicity approximately equal to the wavelength of the incident light and with direction perpendicular to the laser polarization, except in a few special cases that combine angle of incidence and polarization to perturb the pattern symmetry 25,27 . For studies on single-crystal substrates 20,21,[27][28][29][30] , no lattice-polarization angle dependence was observed. To date, ripple formation has been explained in terms of interference effects between the light beam and the lightinduced waves established on the heated surface 32,33 .…”

“…We found that the same grid structure and orientation were reproduced using circular polarization, which likewise projects an equal polarization along all lattice bonds. The pattern type and orientation is thus principally determined by the overlap between the polarization and directional surface states, rather than collective surface wave excitations of previous laserinduced patterns [20][21][22][23][24][25][26][27][28][29][30][31][32][33] . Our observations of structures with period less than 20 nm for small etch depths are consistent with a highly localized light-material interaction.…”

Periodic and uniform nanogratings formed on cemented carbide by femtosecond laser scanning

“…Recent studies show that laser induced periodic surface structures (LIPSSs) on various materials (including metals [1,2], semiconductors [3,4], and insulators [5,6]) have been investigated extensively using femtosecond laser. According to the periods of LIPSSs, the LIPSSs can be divided into two types [7,8].…”