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26LP-I-7
Selective ablation of nano-layer thin films by single-pulse femtosecond laser irradiation
B. Gakovic1, S. Petrovic1, S. Kudryashov2, P. Danilov2, E. Skoulas3, G. Tsibidis3, A. Ionin2, E. Stratakis3
1Vinca Institute of Nuclear Sciences- University of Belgrade, Atomic Physics Department, Belgrade, Serbia
2Lebedev Physical Institute, Basov Quantum Electronics Department, Moscow, Russian Federation
3Foundation for Research and Technology-Hellas FORTH, Institute of Electronic Structure and Laser, Heraklion, Greece
Laser processing of materials is a unique method, which allows their morphological and composition alterations. In the case of ultra-short laser pulses, laser processing is extremely precise. Irradiation of materials by femtosecond laser enables removal or change of their surface at nano/micro level. Nano layer thin films (NLTF) are attractive composite materials due to their properties that cannot be obtained in the case of materials of the same bulk constituents. Selective ablation of the upper layer of the nano-layer thin film, with little or no damage to the layer or the substrate beneath, is significant for application and theory1-3.
In this talk, we are discussing results concerning the selective ablation of a layer/layers from the surface of several MLTF by femtosecond laser pulses. Experimental samples, composed of metallic bilayers (Ni/Ti, Cr/Ti, and Zr/Ti), were prepared by ion sputtering on a Si substrate. Single-pulse irradiations were done in the air with focused and linearly polarized Gaussian laser beams - 515 nm or 1026 nm wavelength and 200 fs or 170 fs pulse duration, respectively. One-step selective ablations of the upper layer, from NLTFs at low laser pulse energies, and complete ablation of the thin films from the Si substrate at higher pulse energies, were registered. The effects of laser-induced morphological and composition changes were monitored by scanning electron microscopy (SEM&EDS) and profilometry. Spallation is appointed to be one of the main mechanisms that caused selective ablation of the upper layers from the NLTF.
References
[1] B. Gakovic, G. D. Tsibidis, E. Skoulas, S.M. Petrovic, B. Vasic, and E. Stratakis, Journal of Applied Physics 122 (2017) 223106.
[2] S.A. Romashevskiy, P.A. Tsygankov, S.I. Ashitkov, MB. Agranat, Applied Physics A, 124 (2018) 376.
[3] S.I. Kudryashov, B. Gakovic, P. A. Danilov, S.M. Petrovic, D. Milovanovic, A.A. Rudenko, A.A. Ionin, Applied Physics Letters, 112 (2018) 023103.
