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Laser-Induced Damage and Ablation of Dielectrics with Few-Cycle Laser Pulses

Talisa, Noah Brodzik
http://orcid.org/0000-0002-0696-7023
http://rave.ohiolink.edu/etdc/view?acc_num=osu1609243476481238

Abstract Details

2020, Doctor of Philosophy, Ohio State University, Physics.
Like many problems in physics, the interaction between high intensity laser pulses and solid materials depends critically on the relative timescales of the drive (the laser pulse with finite duration) and the material response. This is especially true for Laser-Induced Damage and Ablation (LIDA) of solids, where femtosecond (1 fs = 10e−15 s) laser pulses can achieve extremely high energy densities since there isn’t enough time for energy to diffuse away during the laser pulse like there is for picosecond (10e−12 s) and nanoseond (10e−9 s) pulses,for example. The pulse duration dependence of fs-LIDA for Near-Infrared (NIR) pulses less than 100 fs is less well-understood, especially in the Few-Cycle Pulse (FCP) regime (<10fs) where energy is deposited faster than almost all of the processes associated with the material response. In this thesis, the pulse duration dependence of LIDA of transparent dielectric material systems down to the FCP regime is studied using a well-established time-and space-resolved imaging technique as well as high-resolution depth-profiling. LIDA of dielectric solids has large application spaces in precision micro-machining andsurface patterning, as well as improving the LIDA performance of dielectric thin-film opticsto increase the output of high power laser systems. Practical multilayer thin-film opticsintroduce more complexity to the LIDA process due to thin-film interference, so I startedwith a study of FCP-LIDA of the simplest thin-film system: a single layer. I found that dif-ferences in LIDA between two film thicknesses are exacerbated by Few-Cycle Pulses (FCPs)relative to 100 fs pulses. I wrote a Finite-Difference Time-Domain (FDTD) simulation thatmotivates a possible mechanism for this, suggesting FCPs result in a more spatially non-uniform excitation of the films. My results show that the models I used must be extendedto more completely describe my experimental observations. The complexity of the thin-film systems was systematically increased by studying double- and quad-layer thin-film systems that more closely resemble practical optics. I observed significant differences in the dynamics of the material removal stage of LIA between FCPs and 110 fs pulses, despite the fact that energy deposition finishes well before the onset of material removal for both pulse durations. I propose that this is caused by differences in the distribution of deposited energy within the thin-film systems, which affects the expansion process. Finally, I present preliminary results of a study of the pulse duration dependence of the electronic dynamics associated with fs-LIDA of glass. I found that the way the measured signal scales with pulse fluence (areal energy density of the incident pulse) is significantly different between FCPs and 110 fs pulses, pointing towards a fundamental difference in the initial FCP excitation process. I propose mechanisms to explain this and describe future plans to test my hypotheses.
Enam Chowdhury (Advisor)
Gregory Lafyatis (Committee Member)
Thomas Lemberger (Committee Member)
Douglass Schumacher (Committee Member)
235 p.
Condensed Matter Physics; Electromagnetism; Optics; Physics; Plasma Physics; Solid State Physics
Lasers; Femtosecond Lasers; Few cycle pulses; hollow-core fiber; thin-films; optical thin-films; Laser-Induced Damage; Laser-induced ablation; laser ablation; time-resolved; pump-probe; Ultrafast; dielectrics; Spectral broadening; Self-phase modulation

Recommended Citations

Citations

  • Talisa, N. B. (2020). Laser-Induced Damage and Ablation of Dielectrics with Few-Cycle Laser Pulses [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1609243476481238

    APA Style (7th edition)

  • Talisa, Noah. Laser-Induced Damage and Ablation of Dielectrics with Few-Cycle Laser Pulses. 2020. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1609243476481238.

    MLA Style (8th edition)

  • Talisa, Noah. "Laser-Induced Damage and Ablation of Dielectrics with Few-Cycle Laser Pulses." Doctoral dissertation, Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1609243476481238

    Chicago Manual of Style (17th edition)

osu1609243476481238
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© 2020, some rights reserved.Creative Commons License Laser-Induced Damage and Ablation of Dielectrics with Few-Cycle Laser Pulses by Noah Brodzik Talisa is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by The Ohio State University and OhioLINK.
Release 3.2.12