Ultrafast dynamic ellipsometry of laser driven shock waves

The experimental measurement technique of ultrafast dynamic ellipsometry (UDE) was developed for measuring material motion and changes in optical properties of samples under laser driven shock loading. Ultrafast dynamic ellipsometry, a technique based on space-shifted spectral interferometry, uses the time-dependent frequency of a chirped laser pulse to provide time encoding, allowing the picosecond probing of material dynamics in a single shot. With this technique, the sample is probed at two different incident angles with both s- and p-polarized light, which measures the motion of the material and any change in its complex refractive index. Ultrafast dynamic ellipsometry was first used to ascertain the Hugoniot and the shocked refractive indices of thin polymer films of polycarbonate, poly(methyl methacrylate) (PMMA), poly(chlorotrifluoroethylene-co-vinylidene fluoride) (Kel-F 800), and polydimethylsiloxane (Sylgard 184). Next, UDE was used to measure the Hugoniots of liquid samples over a range of nearly one-dimensional stresses in a single laser shot by capitalizing on the spatial energy distribution of the shock generating laser beam. Using the spatially resolved UDE data, the Hugoniots and shocked refractive indices of cyclohexane, toluene, methanol, and water were measured, each in a single laser shot. Two additional liquids, nitromethane and carbon disulfide, were also investigated with UDE, and both liquids showed evidence of chemical reaction in the first 200 ps after the arrival of the shock wave. Ultrafast dynamic ellipsometry was used in conjunction with high-speed schlieren imaging to determine the nature of the insult provided by ablation of a thin titanium film in optical detonators.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2008

Author dc:creator

• Bolme, Cynthia Anne

Advisor dc:contributor.advisor

• Keith A. Nelson.

• Chemistry.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/45160

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/45160