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3Processes accompanying ablation of thin-film and bulk chalcogenide glass As2Se3 under multipulse femtosecond laser
irradiation
A. Shamova*, D. Polyakov, G. Shandybina
ITMO University, 49 Kronverksky Ave, Saint Petersburg, Russia, 197101
Femtosecond laser processing opens up new prospects for chalcogenide glasses for use in optoelectronics and photonics due to a wide change in their structural properties [1]. From the point of view of near- and mid-infrared optics, the most promising materials are glassy arsenic chalcogenides, in particular arsenic selenide As2Se3. At high laser radiation intensities the presence of the toxic element (arsenic) requires a thorough study of damage mechanisms. Currently, a complete picture of glassy arsenic chalcogenides ablation under femtosecond laser irradiation, as well as the accompanying modification processes through the formation of surface periodic nano- and microstructures, has not been developed [1-3], which complicates the industrial implementation of femtosecond laser technology.
The report presents the results of an experimental and theoretical study of ablation processes in thin-film and bulk arsenic selenide As2Se3 under the influence of femtosecond laser pulses in the visible and near-IR ranges depending on pulse energy, number, and repetition rate. The morphological features of irradiated samples and the chemical composition of laser ablation products were studied using digital optical microscopy and Raman spectroscopy.
The experimental results are compared with the results of numerical modeling of the spatiotemporal distribution of As2Se3 film optical properties performed within the framework of n-TTM model [4]. A mechanism has been proposed for the formation of previously unobserved microstructures on As2Se3 thin film surface with a period on the order of the wavelength, oriented parallel to the polarization vector.
Theoretical estimates of accumulative heating of the bulk chalcogenide glass As2Se3 surface allowed us to propose that in the megahertz range of femtosecond pulse repetition rates, redox processes develop in the vapor phase, which contributes to the formation of amorphous selenium and toxic arsenolite crystals (As2O3) in the deposition products.
The results are important for the creation of elements based on chalcogenide glasses for use in high-power laser systems.
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[2] Q. Li, D. Qi, X. Wang, X. Shen, R. Wang, K. Tanaka, Femto-and nano-second laser-induced damages in chalcogenide glasses, Japanese Journal of Applied Physics, vol. 58, pp. 080911, (2019).
[3] K.T. Paula, N.S. Dutta, J.M. Almeida, L.K. Nolasco, M.B. Andrade, C.B. Arnold, C.R. Mendonja, Femtosecond laser induced damage threshold incubation and oxidation in As2S3 and As2Se3 thin films, Applied Surface Science, vol. 654, pp. 159449, (2024).
[4] D.S. Polyakov, G.D. Shandybina, A.A. Shamova, Ultrafast changes of optical properties of semiconductors at wavelength near the edge of interband absorption after excitation by femtosecond laser pulse, Optik, vol. 256, pp. 168751, (2022).
