Yu. S. Gulina, J. Zhu, A. V. Gorevoy, N. I. Dolzhenko, P. A. Danilov, E. N. Rimskaya, S. I. Kudryashov, “Nonlinear absorption of 1030-nm ultrashort laser pulses in polymethyl methacrylate”, Pis'ma v Zh. Èksper. Teoret. Fiz., 2025, Volume 122, Issue 1,Pages <nobr>36

This article is cited in 4 papers

OPTICS AND NUCLEAR PHYSICS

Nonlinear absorption of 1030-nm ultrashort laser pulses in polymethyl methacrylate

Yu. S. Gulina^a, J. Zhu^a, A. V. Gorevoy^a, N. I. Dolzhenko^b, P. A. Danilov^a, E. N. Rimskaya^a, S. I. Kudryashov^a

^a Lebedev Physical Institute, Russian Academy of Sciences, Moscow, 119991 Russia
^b Bauman Moscow State Technical University, Moscow, 105005 Russia

Abstract: The nonlinear interaction of $250$-fs laser pulses at a wavelength of $1030$ nm with polymethyl methacrylate is investigated using an optimized $z$-scan technique. It is shown that the mechanism of pulse attenuation for peak intensities below $0.65$ TW/cm$^2$ can be described as four-photon absorption with the coefficient $\beta_4 = (35\pm5)$ cm$^5$/TW$^3$. The nonlinear refractive index ${n_2} = (7.6\pm0.4)\times10^{-4}$ cm$^2$/TW and the critical power for the onset of self-focusing $P_{\text{cr}}= (1.42\pm0.08)$ MW are determined and these results are used to demonstrate the correspondence between the calculated shift of the nonlinear focal point and the location of the laser-modified regions.

Received: 19.05.2025
Revised: 26.05.2025
Accepted: 27.05.2025

DOI: 10.31857/S0370274X25070054