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Graduate Exam Abstract


Klaus Hartinger

Ph.D. Final

October 30, 2008, 2 pm

Clark C146

Propagation and frequency conversion in the presence of coherent nuclear motion


Abstract: We have investigated linear as well as nonlinear propagation e?ects on a relatively weak ultrashort pulse arising from coherent nuclear motion. To this end, we have developed ana- lytical and numerical models used to calculate the molecular response to a strong, ultrashort pump pulse, and propagate a weak probe pulse in the presence of the nuclear wave packet. The molecular response is described in terms of an ”e?ective” susceptibility, which can be split into linear and nonlinear contributions. While a lot of what is discussed in terms of propagation e?ects is applicable to both rotational and vibrational wave packets, molecular alignment, i.e., coherent rotational motion of linear molecules, is where the focus lies. We have applied spectral interferometry to detecting molecular alignment, both in scanning and single-shot con?gurations, to observe propagation e?ects due to the e?ective linear suscepti- bility and carried out calculations and measurements showing the dependence of the e?ective third-order susceptibility on coherent nuclear motion. Lastly, a strongly enhanced conversion e?ciency to the third harmonic from a relatively weak probe pulse is observed in a variety of molecular and atomic gases.

Adviser: Randy Bartels
Co-Adviser: none
Non-ECE Member: Siu-Au Lee
Member 3: Carmen Menoni
Addional Members: none

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