Tailoring nonlinear temperature profile in laser-material processing
| buir.advisor | İlday, Fatih Ömer | |
| dc.contributor.author | Kesim, Denizhan Koray | |
| dc.date.accessioned | 2019-04-24T05:55:16Z | |
| dc.date.available | 2019-04-24T05:55:16Z | |
| dc.date.copyright | 2019-03 | |
| dc.date.issued | 2019-03 | |
| dc.date.submitted | 2019-04-22 | |
| dc.description | Cataloged from PDF version of article. | en_US |
| dc.description | Thesis (Ph.D.): Bilkent University, Department of Electrical and Electronics Engineering, İhsan Doğramacı Bilkent University, 2019. | en_US |
| dc.description | Includes bibliographical references (leaves 58-63). | en_US |
| dc.description.abstract | Ablation cooled material removal opened up great opportunities for understanding nonlinear processes. Especially using lasers as a tool to tailor nonlinear temperature gradient of material and engineering them to achieve effects such as high ablation efficiency, speed, and low collateral damage. Numerical simulations showed such engineering of the temperature gradient of material is possible for any repetition rate falling inside the ablation cooling regime. Two temperature model is used to investigate the effects of repetition rate, pulse energy, and burst duration. Simulations suggest ablation can continue indefinitely as burst duration increases. They also suggest there is an optimum pulse energy for any repetition rate in terms of efficiency of ablation regarding the material. The results of the simulations are confirmed by experiments using lasers with 1.6 GHz, 1.46 GHz, and 13 GHz repetition rate on biological and technical materials. The ablation threshold for a single pulse is lowered 100 times compared to our previous publication. Finally, related studies that can build upon the shown results are presented. A new thin-disk laser oscillator scheme is proposed that implements mode-locking regimes already established in fiber lasers. Dissipative soliton and similariton simulation results are promising for further studies. They can achieve high energy pulses with the help of nonlinear effects instead of limited by it. Then, a new computer generated hologram algorithm is explained where hundreds of layers can be generated from a single hologram. The algorithm utilizes diffusion as a tool to increase the degree of freedom which in turn decreases the cross-talk between layers. | en_US |
| dc.description.provenance | Submitted by Betül Özen (ozen@bilkent.edu.tr) on 2019-04-24T05:55:16Z No. of bitstreams: 1 10243847.pdf: 31126499 bytes, checksum: 22b10167dfbefd76599901070b70fe72 (MD5) | en |
| dc.description.provenance | Made available in DSpace on 2019-04-24T05:55:16Z (GMT). No. of bitstreams: 1 10243847.pdf: 31126499 bytes, checksum: 22b10167dfbefd76599901070b70fe72 (MD5) Previous issue date: 2019-04 | en |
| dc.description.statementofresponsibility | by Denizhan Koray Kesim | en_US |
| dc.embargo.release | 2019-10-22 | |
| dc.format.extent | xii, 77 leaves : illustrations, charts ; 29 cm. | en_US |
| dc.identifier.itemid | B155919 | |
| dc.identifier.uri | http://hdl.handle.net/11693/50912 | |
| dc.language.iso | English | en_US |
| dc.rights | info:eu-repo/semantics/openAccess | en_US |
| dc.subject | Burst mode | en_US |
| dc.subject | Laser material processing | en_US |
| dc.subject | Ablation cooling | en_US |
| dc.subject | Ultrashort pulses | en_US |
| dc.subject | Nonlinear system | en_US |
| dc.subject | Thermal profile | en_US |
| dc.title | Tailoring nonlinear temperature profile in laser-material processing | en_US |
| dc.title.alternative | Doğrusal olmayan sıcaklık profilinin lazer materyal işleme için düzenlenmesi | en_US |
| dc.type | Thesis | en_US |
| thesis.degree.discipline | Electrical and Electronic Engineering | |
| thesis.degree.grantor | Bilkent University | |
| thesis.degree.level | Doctoral | |
| thesis.degree.name | Ph.D. (Doctor of Philosophy) |