Interference Between Different Optical Processes
This thesis reports an experimental study of an interference phenomenon between one-photon and three-photon 6s^1S_0-6p ^1P_1 transition amplitudes in a vapor of atomic mercury. The interference was observed by monitoring the multiphoton ionization signal. Using a three-cell design we were able to separate the third -harmonic generation process and the interfering absorption processes such that we could externally control the relative phase between the two transition amplitudes and directly study the interference phenomena. We observed that the multiphoton ionization signal, which is a measure of the net transition moment, varied sinusoidally as the relative phase increased. Using an eight-electrode design to collect the electrons ionized at different positions along the beam axis around the focal region, we measured the phase shift of the interference due to the pi phase shift of a focused Gaussian beam propagating through the focal region. The experimental setup and the experimental procedure are discussed in detail. This new method can be used in the study of many phase sensitive processes including potential applications in coherent control of chemical reactions.
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- COHERENT CONTROL;
- Engineering: Electronics and Electrical; Physics: Optics; Physics: Atomic