A comparative study on surface modifications induced in a dielectric material and a metal using femtosecond laser

Author

Naveen Kumar Kondameedi

Abstract

"Quartz (Dielectric) and Galvanized Iron (Metal) were tested with respect to their response when irradiated with 120 fs laser pulses at various pulse energies and pulse numbers. Theoretical models governing their ablation mechanisms were reported and comparative results on the investigations were analyzed. The experiments were carried out in air within fluence ranges between 0.7 J/mm² to 700 J/mm². A combination of energy per pulse between 0 .0lxl0^-3 W to 0 .2 x10^-3 W and number of pulses between 1 and 50 were used. The changes induced in the surface morphologies were analyzed with Optical Microscope, SEM and FESEM. From the experimental data and calculated incident energy density, damage threshold diameters and ablation depth were calculated to explain lateral & vertical precision and published modeling results were verified. After the observations, it was concluded that low fluence regime below 70 J/mm² with a combination of low energy per pulse (< 0.1 x 10^-3 W) and moderate number of pulses (between 10 & 25) is a better way to machine the target materials using the Femtosecond laser machining system addressed in this work. Finally, considering the fact that laser ablated areas undergo severe thermal and mechanical stresses which results in increased hardness & elasticity, a method to preferentially fabricate materials with desired hardness on surfaces is proposed"--Abstract, p. iii

Advisor(s)

Tsai, Hai-Lung

Committee Member(s)

Wan, Kai-Tak
Miller, F. Scott, 1956-

Department(s)

Mechanical and Aerospace Engineering

Degree Name

M.S. in Mechanical Engineering

Publisher

University of Missouri--Rolla

Publication Date

Spring 2007

Pagination

xi, 58 pages

Note about bibliography

Includes bibliographical references (pages 55-57)

Rights

© 2007 Naveen Kumar Kondameedi, All rights reserved.

Document Type

Thesis - Restricted Access

File Type

text

Language

English

Subject Headings

Femtochemistry
Laser pulses, Ultrashort
Laser spectroscopy

Thesis Number

T 9161

Print OCLC #

173650015

Recommended Citation

Kondameedi, Naveen Kumar, "A comparative study on surface modifications induced in a dielectric material and a metal using femtosecond laser" (2007). Masters Theses. 5974.
https://scholarsmine.mst.edu/masters_theses/5974