Nanostructure and microripple formation on the surface of sapphire with femtosecond laser pulses

Abstract

We have demonstrated the creation of polarization-dependent nanogratings with a period of about 250 nm on the surface of sapphire by scanning the femtosecond laser beam with appropriate irradiation conditions. Laser fluence range for nanograting self-formation was very narrow in the slow scan mode. The grating depth variation was observed with atomic force microscope image analysis. To see the composition distribution in the nanostructure, we carried out the Auger signal analysis. In addition, we found a new periodic structure with a period of a few μm and discussed the complex formation mechanism.

Femtosecond laser induced phenomena in transparent solid materials: Fundamentals and applications

“…The origin of the HSFLs is still under debate in the literature. Different mechanisms such as SHG, self-organization, interference, nanoplasmonics and standing wave have been proposed [261,262,265,281]. A threshold effect of nanograting generation is confirmed by the observation of switching from smooth modification to appearance of nanogratings [282].…”

“…Femtosecond laser induced periodic surface structures (fs-LIPSSs) on the various materials, such as metals, semiconductors, and dielectrics, have gained considerable attraction and hold many potential applications in photonics, plasmonics, optoelectronics, thermal radiation sources and bio-optical devices [260][261][262][263][264][265][266]. LIPSSs are also referred to ripples or gratings.…”

“…The possibility of modifying the refractive index of the local region in transparent materials by the use of focused intense femtosecond near-infrared laser pulses from a Ti:sapphire laser at 800 nm has attracted a lot of attention during the past several years mainly due to the localized refractive index change allowing for creating the building blocks of more complex photonic systems embedded in optical materials [70,82,[85][86][87]96,98,262]. The first pioneering work was conducted by H. Misawa in Matsuhara Microphotoconversion Project, Japan Science and Technology Agency.…”

The Fabrication of Micro/Nano Structures by Laser Machining

“…These 3D micropatterning and multilayer structures can provide more potential applications for graphene-based devices [262]. In 2012, D. Kim et al proved that polarization-dependent nanomaps with a period of about 250 nm were produced on the sapphire surface by scanning the femtosecond laser beam under appropriate illumination conditions [263].…”

Subwavelength ripple formation on planar and nonplanar surfaces by femtosecond laser scanning

“…In order to achieve a controllable fabrication for the requirements of variant applications most efforts have focused on determining the formation mechanism of these characteristic subwavelength structures, such as the interference between a surface plasmon and incident laser [12,27] , surface plasmon effects [28][29][30] , initial surface roughness [24,31,32] , kinds of heating [21,33] , resonant Mie scattering [34,35] , and so on. Another typical mechanism was reported by Sakabe et al [36] in which the parametric decay resulting from stimulated Raman scattering (SRS) was suggested as a logical physical mechanism and an expression to evaluate the SSP of ripples was presented.…”