CC BY
14LM-O-19
Three-dimensional hybrid optoacoustic imaging of the laser-induced plasma and deposited energy density under femtosecond laser excitation of condensed medium
Rumiantsev B.V.1, Mareev E.I.12, Bychkov A.S.13, Karabutov A.A.3, Makarov V.A.13, Cherepetskaya E.B.1'3 and Potemkin F.V.1
1 - Faculty of Physics, Lomonosov Moscow State University, Leninskie Gory bld.1/2, 119991 Moscow, Russia.
2 - Institute of Photonic Technologies FSRC "Crystallography and Photonics," RASS, Troitsk 108840, Russia.
3 - The National University of Science and Technology MISiS, Leninski Prospect 6, Moscow 119991, Russia.
rumjancev. bv15@physics. msu. ru Femtosecond laser processing at the present time is an area of the active scientific research and has a prospective for the transition into the field of technological applications in the near future. The subjects of special interest in this area is the femtosecond laser micromachining of the bulk waveguides [1] in the field of optoelectronics, femtosecond laser processing in the biophotonics and medicine [2] and ultrafast femtosecond processing of the bulk dielectrics [3]. Technological applications of the femtosecond laser processing requires use of the feedback allowing determination of the deposited energy density (DED, kJ/cm3) distribution. The measurement of the plasma electron density distribution (cm-3) can provide this feedback, since the plasma formation process directly precedes the energy transfer under plasma-mediated laser impact on the condensed medium bulk and therefore the measured electron density can be directly recalculated to the DED. In the present work the method of the three-dimensional optoacoustic imaging is developed and experimentally realized. The proposed method allows measurement of the three-dimensional distributions of the plasma electron density and DED under plasma-mediated laser impact on the condensed medium (Fig.1), that can't be achieved by any other modern techniques. As an experimental medium for the proof of method concept the distilled water was used. The proposed method is based on the shadowgraphy [4] and photoacoustic imaging techniques [5].
Fig. 1. A) 3D distribution of the probe pulse absorption in the plasma volume. B) 3D distributions of the plasma electron density and DED.
The work was supported by the RSF grant no. 17-72-20130. Rumiantsev B.V. is the scholar of the foundation for the advancement of the theoretical physics and mathematics "BASIS".
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[3] Butkus, Simas, et al. "Rapid cutting and drilling of transparent materials via femtosecond laser filamentation." Journal of Laser Micro Nanoengineering 9.3 (2014): 213.
[4] Rumiantsev, Boris, et al. "Photoacoustic and optical imaging of the femtosecond filament in water." Nonlinear Optics and Applications XI. Vol. 11026. International Society for Optics and Photonics, 2019.
[5] Potemkin, F. V., et al. "Two-dimensional photoacoustic imaging of femtosecond filament in water." Laser Physics Letters 15.7 (2018): 075403.
