Thermal-induced effects on ultrafast laser filamentation in ethanol


Tan, H. Y. and Ong, Guang Liang and Nee, Chen Hon and Yap, Seong Ling and Poh, Hun Seng and Tou, Teck Yong and Lan, B. L. and Lee, S. F. and Yap, S. S. (2023) Thermal-induced effects on ultrafast laser filamentation in ethanol. Optics & Laser Technology, 163. p. 109350. ISSN 00303992

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Fs laser filamentation in ethanol is studied for bottom-up nanomaterials synthesis at different laser repetition rate. Measurements of energy loss, visible conical images, transmitted beam profile and the optical emission spectra show that laser repetition rate affects ultrafast laser filamentation in ethanol significantly because of the induced thermal processes. Firstly, near the threshold laser energy for self-focusing, high laser repetition rate could interfere with the process, via thermal defocusing that inhibits the onset of filamentation. An enlarged, near flat-top laser beam is produced for the conditions that favor thermal lensing. Secondly, at high laser energy, thermal defocusing effect is saturated as convective heat dissipation occurs. Thus, self-focusing prevailed and led to filamentation at all repetition rates. The strong convection at high laser repetition rate increases the rate of reactions for nanodiamonds synthesis, as the flow of fresh ethanol precursor to the localized filamentation zone is enhanced.

Item Type: Article
Uncontrolled Keywords: Ultrafast laser filamentation, Nanodiamonds, Repetition rate, Critical power, Thermal lensing, Thermo-optic coefficient
Subjects: Q Science > QC Physics > QC350-467 Optics. Light
Divisions: Faculty of Engineering (FOE)
Depositing User: Ms Nurul Iqtiani Ahmad
Date Deposited: 11 Apr 2023 02:51
Last Modified: 11 Apr 2023 02:51


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