Phonon-polaritons in bulk and patterned materials

This thesis explores the spectroscopic properties of phonon-polaritons, which are admixtures of coupled electromagnetic and mechanical vibrations in polar crystals. An in-depth theoretical treatment supplemented with simulations of experimental results of a four-wave mixing impulsive stimulated Raman scattering (ISRS) method to generate and probe polaritons with arbitrary wavevectors is developed. A novel method to generate phonon-polaritons with high amplitudes via focusing is also presented. The motivation for this work is ultimately the generation of lattice oscillations with high amplitude that will permit exploration of the potential energy surface of collective vibrational motion beyond its linear regime. Femtosecond laser machining has been used to fabricate microstructures in lithium niobate and lithium tantalate. Phonon-polaritons propagation has been extensively characterized in a number of functional elements, including waveguides, resonators, and various diffractive, reflective, and focusing elements. The experimental results are supplemented by two-dimensional finite-difference time-domain simulations of polariton generation and propagation in arbitrary two-dimensional patterned structures. The phonon-polaritons studied have THz frequencies and propagate at lightlike speeds. The motivation for this research is the development of a versatile terahertz spectroscopy platform, in which phonon-polaritons are used as a source of THz radiation. Furthermore, these fabricated microstructures can serve as the basic building blocks of an intergrated platform in a single crystal where phonon-polaritons are used for ultrafast signal processing.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2003

Author dc:creator

• Stoyanov, Nikolay Staykov, 1979-

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/1721.1/29954

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/29954