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Ultrafast Mid-Infrared Laser-Solid Interactions

Werner, Kevin Thomas
http://rave.ohiolink.edu/etdc/view?acc_num=osu1546542784608798

Abstract Details

2019, Doctor of Philosophy, Ohio State University, Physics.
This dissertation presents a study of the fundamental mechanisms of ultrafast mid-infrared laser-solid interactions, focusing on semiconductors. Laser intensities both above and below the laser-induced damage threshold are used in this study. Despite a recent increase in interest in both applications and fundamental mechanisms, the mid-infrared wavelength regime has hardly been studied previously with ultrashort pulses. New ultrafast mid-infrared laser sources allow for increased access to this regime of laser-solid interaction. An ultrafast, mid-infrared optical parametric amplifier was designed, fabricated, and characterized. The construction of this optical parametric amplifier has led to many experiments and collaborations, which are presented in this dissertation. Measurements of single and multi-pulse laser induced damage thresholds were studied in silicon as a function of mid-infrared wavelength. Additionally, unique morphology was studied with a wide array of imaging techniques. The results of these studies were compared to existing theoretical models and experiments with near-infrared, visible, and ultraviolet wavelengths. We find that further modification to existing models and/or new models are needed to explain the data. Our computational efforts, while they don’t show good matching to the experimental data, will contribute to future studies in this area. Experimental studies and numerical simulations were also performed with intensity below the laser induced damage threshold. Polycrystalline zinc selenide is an exciting source of broadband supercontinuum and high-harmonic generation via random quasi phase matching, exhibiting broad transparency in the mid-infrared (0.5-20 μm). The effects of wavelength, pulse power, intensity, propagation length, and crystallinity on supercontinuum and high harmonic generation are investigated experimentally using ultrafast mid-infrared pulses. Observed harmonic conversion efficiency scales linearly in propagation length reaching as high as 36%. For the first time to our knowledge, n2 is measured for mid-infrared wavelengths in ZnSe: n2(λ=3.9 μm)=(1.2±0.3×10-14 cm2/W). Our n2 measurement is applied to simulations modeling high-harmonic generation in polycrystalline ZnSe as an effective medium using unidirectional pulse propagation simulations. Good matching to the experimental results is found, and the model suggests the harmonics are generated by cascaded harmonic generation.
Enam Chowdhury (Advisor)
Jay Gupta (Committee Member)
Douglas Schumacher (Committee Member)
Linn Van Woerkom (Committee Member)
200 p.
Physics
MIR; Mid-Infrared; Femtosecond; Ultrafast; Silicon; Si; Zinc Selenide; ZnSe; Laser Induced Damage; Ablation; Breakdown; Melting; Random Quasi Phase Matching; Metasurfaces; Optical Parametric Amplifier

Recommended Citations

Citations

  • Werner, K. T. (2019). Ultrafast Mid-Infrared Laser-Solid Interactions [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1546542784608798

    APA Style (7th edition)

  • Werner, Kevin. Ultrafast Mid-Infrared Laser-Solid Interactions. 2019. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1546542784608798.

    MLA Style (8th edition)

  • Werner, Kevin. "Ultrafast Mid-Infrared Laser-Solid Interactions." Doctoral dissertation, Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1546542784608798

    Chicago Manual of Style (17th edition)

osu1546542784608798
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© 2019, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.