Polaritonics : an intermediate regime between electronics and photonics

This thesis contains the foundational work behind the field of polaritonics. Corresponding to a frequency range from roughly 100 gigahertz up to 10 terahertz, polaritonics bridges the gap between electronics and photonics. In this regime, signals are carried by an admixture of electromagnetic and lattice vibrational waves known as phonon-polaritons, rather than currents or photons. Impulsive stimulated Raman scattering (ISRS) is employed for phonon-polariton generation, whereby lattice vibrations are driven by optical femtosecond laser pulses directed into ferroelectric LiNbO3 or LiTaO3. The vibrational amplitude is proportional to the intensity of the excitation pulses. Due to the high dielectric constants of these crystals, phonon-polaritons travel in a predominantly lateral direction away from the excitation region. Lateral propagation is further facilitated by employing crystals whose thickness is on the order of the phonon-polariton wavelength, such that propagation occurs within one or more of the slab waveguide modes of the crystal. Direct observation of phonon-polaritons is achieved using real-space imaging, which monitors and records the spatiotemporal evolution of phonon-polaritons within a ferroelectric crystal. The details of both broadband and narrowband phonon-polariton generation and propagation in bulk and thin film crystals are presented. Additionally, robust polaritonic waveform generation is illustrated that relies on temporal or spatial shaping of the optical excitation pulses. Guidance, control, and other types of signal processing are demonstrated by patterning of the host crystal using femtosecond laser micromachining.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Ward, David W. (David Wayne), 1970-

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/1721.1/27873
• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Identifier URI

http://dspace.mit.edu/handle/1721.1/27873

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/27873