Shiell, Ralph C
Precision Measurements Using Semiconductor Light Sources: Applications in Polarimetry and Spectroscopy
This thesis comprises two parts:Part I describes a method to improve the accuracy with which the polarization state of light can be characterized by the rotating quarter-wave plate technique. Through detailed analysis, verified by experiment, we determine the positions of the optic axes of the retarder and linear polarizer, and the wave plate retardance, to better than 1° for typical signal-to-noise ratios. Accurate determination of the Stokes parameters can be achieved using this technique to determine the precise retardance at each of the wavelengths of interest. In Part II, a theoretical analysis of the Fabry-Perot interferometer and its application to quantitative absorption spectroscopy is presented. Specifically the effects of broadening due to non-monochromatic light sources and examples of non-ideal etalon surfaces on the visibility of absorption features are investigated. The potential of this type of spectrometer for ethanol detection in a portable breath analysis application is discussed.
Author Keywords: ABSORPTION SPECTROSCOPY, CALIBRATION, FABRY-PEROT INTERFEROMETER, OPTICS, POLARIMETRY
Heavy Rydberg Photo-dissociation Cross-section Calculations and Experimental Progress Towards Cold Collisions in Lithium
This thesis is divided into two parts, each of which supports constructing and using a lithium magneto-optical trap for cold collision studies:
Part I
One outgoing channel of interest from cold collisions is the production of ion pairs. We describe an effective method for calculating bound-to-continuum cross-sections for charged binary systems by examining transitions to states above the binding energy that become bound when the system is placed within an infinite spherical well. This approach is verified for ionization of a hydrogen atom, and is then applied to the heavy Rydberg system Li+...I-.
Part II
A wavemeter previously built in the lab is redesigned for increased reliability and ease of use by replacing the optical hardware with a rocker system, which can be aligned in mere minutes rather than half a day as was previously the case. The new wavemeter has been tested through saturated absorption spectroscopy of lithium.
Author Keywords: cross-section, dissociation, lithium, magneto-optical trap, Michelson, wavemeter