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Communication Dans Un Congrès Année : 2016

Control of stress and high aspect ratio voids in sapphire and glass using femtosecond Bessel beams

Résumé

Controlling stress applied in glasses and transparent materials by ultrashort pulse lasers is an important issue for several technological fields such as those of display glass cutting. Bessel beams overcome the difficulty of controlling the nonlinear propagation of ultrashort and intense pulses in the material. Since these beams do not distort along the propagation, they produce a homogeneous track of plasma and distribute energy uniformly along the propagation direction. This has been used for laser processing of high aspect ratio channels in glass with single laser shots [1]. Here, we report high aspect ratio single pulse nanochannel drilling in sapphire. Empty void structures can be drilled completely inside sapphire. Bessel beams generate high-aspect ratio micro-explosions capable to open a void by material compaction aside of the channel. This provides evidence of the creation of a pressure well in excess of the Young modulus of the sapphire (0.4 TPa) [2]. At higher energies, we observe crack formation in sapphire. We compare femtosecond and picosecond illumination regimes. Interestingly, at femtosecond pulse durations, cracks mainly follow the polarization state while at 3 ps pulse duration, cracks form along materials axis. Cracks and stress are important parameters for materials cutting. We show for the first time to our knowledge the control of stress induced in glass by modifying the Bessel beam spatial profile. We evaluate the performances of beam profiles by measuring the toughness of laser processed glass slides under 3 points bending test. We anticipate these novel results will widely impact the field of laser processing of transparent materials
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Dates et versions

hal-02300632 , version 1 (29-09-2019)

Identifiants

  • HAL Id : hal-02300632 , version 1

Citer

Ludovic Rapp, Rémi Meyer, Remo Giust, Luca Furfaro, Pierre Lacourt, et al.. Control of stress and high aspect ratio voids in sapphire and glass using femtosecond Bessel beams. High Power Laser and Ablation and Directed Energy conference, Apr 2016, Santa Fe, United States. ⟨hal-02300632⟩
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