scholarly journals Laser induced tunable Ge2Sb2Te5 phase-change gratings

2021 ◽  
Vol 2015 (1) ◽  
pp. 012154
Author(s):  
Pavel I. Trofimov ◽  
Irina G. Bessonova ◽  
Petr I. Lazarenko ◽  
Demid A. Kirilenko ◽  
Nikolay A. Bert ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Change ◽  
Surface Structures ◽  
The Other ◽  
Formation Mechanisms ◽  
Laser Polarization ◽  
Time Cost ◽  
Periodic Surface ◽  
Light Manipulation ◽  
High Flexibility

Abstract Periodic photonic nano- and microstructures are routinely used for light manipulation at the nanoscale. However, their fabrication process is demanding in terms of time, cost and facilities. Here we demonstrate a rapid laser-assisted method for fabrication of gratings in Ge2Sb2Te5 (GST) thin films, based on the formation of laser induced periodic surface structures (LIPSS). LIPSS formation mechanisms dependent on the wavelength of the operating laser, lead to high flexibility of the process, producing gratings with tunable period and orientation with respect to the initial laser polarization. The phase-change properties of GST, on the other hand, allows to fabricate phase gratings with strong modulation of refractive index, which are rewritable in nature.

scholarly journals Tunable laser induced periodic surface structures in Ge2Sb2Te5 thin films

2021 ◽  
Vol 2086 (1) ◽  
pp. 012170
Author(s):  
Irina G Bessonova ◽  
Pavel I Trofimov ◽  
Petr I Lazarenko ◽  
Demid A Kirilenko ◽  
Nikolay A Bert ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Change ◽  
Low Cost ◽  
Beam Steering ◽  
Tunable Laser ◽  
Surface Structures ◽  
Periodic Surface ◽  
Light Localization ◽  
Rapid Fabrication ◽  
Direct Laser

Abstract Planar photonic structures, such as gratings and metasurfaces, are routinely used for beam steering, waveguide coupling, and light localization. However, conventional fabrication techniques that involve lithography are demanding in terms of time and cost. Much cheaper and simpler methods for surface patterning and formation of periodic surface structures are enabled by direct laser processing. Here, we demonstrate low-cost rapid fabrication of high-quality phase gratings based on the formation of laser induced periodic surface structures (LIPSS, or ripples) in Ge2Sb2Te5 (GST) thin films. Due to unique phase change properties of GST, the structures demonstrate strong modulation of refractive index with period controlled by the wavelength of laser irradiation. We study the formation of phase change LIPSS in a broad range of excitation wavelengths and observe transition between regimes with different orientations of generated ripples with respect to laser polarization.

scholarly journals Laser-induced periodic surface structures on bismuth thin films with ns laser pulses below ablation threshold

2017 ◽  
Vol 7 (6) ◽  
pp. 1777 ◽  
Author(s):  
A. Reyes-Contreras ◽  
M. Camacho-López ◽  
S. Camacho-López ◽  
O. Olea-Mejía ◽  
A. Esparza-García ◽  
...  
Keyword(s):  
Thin Films ◽  
Ablation Threshold ◽  
Laser Pulses ◽  
Surface Structures ◽  
Periodic Surface

scholarly journals Formation of Highly Ordered Platinum Nanowire Arrays on Silicon via Laser-Induced Self-Organization

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 1031
Author(s):  
Michael Dasbach ◽  
Hendrik M. Reinhardt ◽  
Norbert A. Hampp
Keyword(s):  
Thin Films ◽  
Nanowire Arrays ◽  
Surface Structures ◽  
Self Organization ◽  
Periodic Patterns ◽  
Periodic Surface ◽  
Platinum Nanowires ◽  
Nanosecond Pulsed Laser ◽  
Sputter Deposited ◽  
20 Nm

Laser-induced periodic surface structures (LIPSS) provide an elegant solution for the generation of highly ordered periodic patterns on the surface of solids. In this study, LIPSS are utilized for the formation of periodic platinum nanowire arrays. In a process based on laser-stimulated self-organization, platinum thin films, sputter-deposited onto silicon, are transformed into nanowire arrays with an average periodicity of 538 nm. The width of the platinum nanowires is adjustable in a range from 20 nm to 250 nm by simply adjusting the thickness of the initial platinum thin films in a range from 0.3 nm to 4.3 nm. With increasing width, platinum nanowires show a rising tendency to sink into the surface of the silicon wafer, thus indicating alloying between platinum and silicon upon LIPSS-formation by a nanosecond-pulsed laser. The Pt/silicon wires may be etched away, leaving a complementary nanostructure in the silicon surface.

scholarly journals Two-Dimensional Periodic Nanostructure Fabricated on Titanium by Femtosecond Green Laser

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1820
Author(s):  
Yi-Hsien Liu ◽  
Shu-Chun Yeh ◽  
Chung-Wei Cheng
Keyword(s):  
Titanium Surface ◽  
Laser Wavelength ◽  
Green Laser ◽  
Surface Structures ◽  
Laser Polarization ◽  
Two Dimensional ◽  
Periodic Surface ◽  
Scanning Strategies ◽  
Periodic Nanostructure ◽  
Sub Wavelength

Laser-induced periodic surface structures (LIPSS) is the sub-wavelength periodic nanostructure, which is generally generated by the femtosecond laser. There are two kinds of LIPSS, low spatial frequency LIPSS (LSFL) and high spatial LIPSS (HSFL), and the period size is close and less than half of the laser wavelength, respectively. Fabrication of two-dimensional (2D) LSFL and HSFL on a titanium surface with a linear-polarized femtosecond green laser beam (wavelength 515 nm) and cross-scanning strategies is demonstrated in this study. Four types of LIPSS structures are obtained by controlling the laser fluence, irradiated pulses, and cross-scanning strategies: 1D-LSFL perpendicular to laser polarization with a period of 300–360 nm, 1D-HSFL parallel to laser polarization with a period of 55–75 nm, 2D-LSFL dot-like structures with a period ~200 nm, and 2D-HSFL net-like structures with a period of 50–100 nm.

scholarly journals Femtosecond Laser-Induced Periodic Surface Structures on Fused Silica: The Impact of the Initial Substrate Temperature

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1340 ◽  
Author(s):  
Stephan Gräf ◽  
Clemens Kunz ◽  
Sebastian Engel ◽  
Thibault Derrien ◽  
Frank Müller
Keyword(s):  
Dielectric Materials ◽  
Fused Silica ◽  
Surface Structures ◽  
Formation Mechanisms ◽  
Spatial Period ◽  
Threshold Fluence ◽  
Periodic Surface ◽  
Initial Substrate ◽  
Fs Laser ◽  
The Impact

The formation and properties of laser-induced periodic surface structures (LIPSS) were investigated upon fs-laser irradiation of fused silica at different initial substrate temperatures, TS. For substrate heating between room temperature, TRT, and TS = 1200 °C, a continuous wave CO2 laser was used as the radiation source. The surface structures generated in the air environment at normal incidence with five successive fs-laser pulses (pulse duration, τ = 300 fs, laser wavelength, λ = 1025 nm, repetition frequency, frep = 1 kHz) were characterized by using optical microscopy, scanning electron microscopy, and 2D-Fourier transform analysis. The threshold fluence of fused silica was systematically investigated as a function of TS. It was shown that the threshold fluence for the formation of low-spatial frequency LIPSS (LSFL) decreases with increasing TS. The results reveal that the initial spatial period observed at TRT is notably increased by increasing TS, finally leading to the formation of supra-wavelength LIPSS. The findings are discussed in the framework of the electromagnetic interference theory, supplemented with an analysis based on thermo-convective instability occurring in the laser-induced molten layer. Our findings provide qualitative insights into the formation mechanisms of LIPSS, which allow improvements of the control of nanostructure formation to be made for corresponding applications of dielectric materials in the future.

Laser-induced modification and formation of periodic surface structures (ripples) of amorphous GST225 phase change materials

2019 ◽  
Vol 113 ◽  
pp. 87-94 ◽  
Author(s):  
Sergey Kozyukhin ◽  
Petr Lazarenko ◽  
Yuri Vorobyov ◽  
Alexander Baranchikov ◽  
Victoria Glukhenkaya ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Surface Structures ◽  
Periodic Surface

scholarly journals Femtosecond Laser-Induced Periodic Surface Structures on Different Tilted Metal Surfaces

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2540
Author(s):  
Yi-Hsien Liu ◽  
Kong-Kai Kuo ◽  
Chung-Wei Cheng
Keyword(s):  
Metal Surfaces ◽  
Incident Angle ◽  
Coupling Factor ◽  
Surface Structures ◽  
Calibration Model ◽  
Laser Polarization ◽  
Inclined Plane ◽  
Periodic Surface ◽  
Tilted Surface ◽  
Electron Phonon Coupling

Laser-induced periodic surface structures (LIPSS) are used for the precision surface treatment of 3D components. However, with LIPSS, the non-normal incident angle between the irradiated laser beam and the specimen surface occurs. This study investigated LIPSS on four different metals (SUS 304, Ti, Al, and Cu), processed on a tilted surface by an s-polarized femtosecond fiber laser. A rotated low spatial frequency LIPSS (LSFL) was obtained on SUS 304 and Ti materials by the line scanning process. However, LSFL on Cu and Al materials was still perpendicular to the laser polarization. The reason for the rotated and un-rotated LSFL on tilted metal surfaces was presented. The electron-phonon coupling factor and thermal conductivity properties might induce rotational LSFL on tilted SUS 304 and Ti surfaces. When fabricating LSFL on an inclined plane, a calibration model between the LSFL orientation and inclined plane angle must be established. Hence, the laser polarization direction must be controlled to obtain suitable LSFL characteristics on a 3D surface.

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