Ultrafast Dynamics and Nonlinear Interactions in Alkali Atoms and Diatomics

Ultrafast laser pump-probe techniques have been used to study the rovibrational dynamics of the B, C, and D states of the Cesium dimer and to study atomic wavepackets and nonlinear effects in Rubidium and Potassium. Two color, pump-probe techniques have been used to probe the time evolution of wavepackets in the B, C, and D rovibrational levels of Cs$\sb2$. The temporal history of the wavepacket is inferred from the time and energy-integrated photoelectron signal produced when the excited state is photoionized by a time-delayed probe pulse. Oscillatory motion is observed in the photoionization signals, corresponding to the vibrational energy differences of the state begin studied. The period of oscillation ranges between 2.2 and 1.1 ps depending on the state. Quantum mechanical simulations of the wavepacket motion show excellent agreement with the experimental data. Experiments have been carried out in which atomic wavepackets interact with a four-wave mixing process in Rb and K to produce spatially and temporally coherent pulses of UV radiation. Wave packets are produced by coherently exciting an ensemble of states using the broad bandwidth of a femtosecond pulse. Oscillations corresponding to the energy differences between the levels in the wavepacket are superimposed on the UV signal when two identical pump and delayed probe pulses are introduced into the alkali vapor. Analyses of the UV emission line profiles show excellent agreement with the four-wave mixing process.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Electrical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• John, Pramod Charles

Contributors dc:contributor

• Eden, J.G.

• Physics, Optics

Language dc:language

eng

Identifier

(MiAaPQ)AAI9737147

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/81186