CC BY
5*
ALT'23 The 30th International Conference on Advanced Laser Technologies
LM-P-12
Pressure pulses generated in metals during picosecond laser ablation
S.I.Kudryashov1, P.A.Pivovarov2, V.I.Priklonskii3, A.A.Samokhin2*, S.Ph.Umanskaya1,
N.V.Chernega1
1-P. N. Lebedev Physical Institute of Russian Acad. Sci., Leninskiy Pr. 53, 119991 Moscow, Russian Federation 2- Prokhorov General Physics Institute of the Russian Academy of Sciences, st.Vavilova 38, Moscow, 119991 Russian
Federation
3- Faculty of Physics Lomonosov Moscow State University, 1 Leninskie Gory, bldg. 2, Moscow, 119234 Russian
Federation
Main author * email address: asam40@mail.ru
The behavior of pressure pulses generated in a metal during picosecond laser ablation is analyzed. The contribution to the formation of such pulses is due to the thermoacoustic and evaporative mechanisms, as well as possible explosive boiling or metal-insulator transition and accompanying hydrodynamic effects. For shorter pulses in this range, the main role is played by the thermoacoustic mechanism, which is realized at a subcritical change in the density of the condensed medium. Analytical and numerical estimates show that, for a certain duration of picosecond exposure, the stationary evaporation regime can be achieved in the region where the evaporation pressure does not yet exceed the contribution from the thermoacoustic mechanism. In this case, in contrast to the nanosecond exposure [1], the change in the main mechanisms of pressure generation with increasing laser intensity may not be accompanied by a sharp change in the pressure increase due to surface evaporation. This behavior is compared with the experimental data obtained on monitoring the recoil pressure in lead and aluminum targets irradiated with 30 ps laser pulses (^=532 nm) in the intensity range I<90 GW/cm2.These data do not show noticeable manifestations of delayed effects after the action of a laser pulse, which were discussed in [2-5] for different laser pulse duration and materials. Questions about observing the effects of explosive boiling or metal-dielectric transition in such a regime of exposure and monitoring also remain open, in particular, due to the limitations of the resolution of pressure sensors. To detect and study such effects, the nanosecond exposure mode is more optimal. Revealing the features of laser ablation of metals due to the presence of a critical liquid-vapor transition point is necessary to clarify the possibility of their use in order to obtain experimental information about the parameters of this point, which continue to be poorly defined for most metals.
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[3] V.I. Vovchenko, S.M.Klimentov, P.A. Pivovarov, et al. Effect of submillisecond radiation of the erbium laser on absorbing liquid, Bull. Lebedev Phys. Inst. 34, 325-328 (2007).
[4] A.A. Samokhin, P.A.Pivovarov, , E.V. Shashkov, et al. On the Metal-Nonmetal Transition under Nanosecond Laser Ablation, Phys. Wave Phen. 29, 204-209 (2021).
[5] A.A. Samokhin, N.N. Il'ichev, A.V. Sidorin, P.A. Pivovarov, Delayed effects in laser ablation, Abstract book of International Conference on Advanced Laser Technologies (ALT) (2022)
