Two nonlinear optical experiments are presented in which the third-order electronic susceptibility of molecules is used to generate Raman signals. The first one uses a single 532 nm beam from a Nd:YAG laser to produce Stimulated Raman Scattering in benzene and deuterated benzene. With a simple experimental set-up, stimulated emission involving CC and CH (CD) stretching modes from both C���H��� and C���D��� can be visually witnessed. Collinear and conical stimulated Raman beams are observed and explained. Measuring the wavelengths of the coherent beams with a meter stick and a grating permits the calculation of CC and CH force constants in benzene. This experiment has been developed as a lab in graduate and undergraduate courses and has been submitted to J. Chem. Ed. for publication. The second experiment uses a high resolution Coherent Anti-Stokes spectrometer to investigate the v��� vibrational mode of the CD��� radical produced by photolysis of CD���I. Calibrated spectra are obtained at much higher resolution than in an earlier published study and efforts are described to improve the range of data and to reconcile differences between the spectra. Modeling of the spectra leads to a "best fit" set of vibration-rotation parameters for CD��� but a completely satisfactory fit of both high and low resolution spectra was not achieved. / Graduation date: 2003

Graduation date 1997

No description available.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1948. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves i-iii).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 338-345).

Thesis (M.S.)--University of Wisconsin--Madison, 1980. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 557-562).

Thesis--University of Wisconsin--Madison. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 350-368).

University of Macau / Faculty of Science and Technology / Department of Computer and Information Science

Stimulated Raman scattering (SRS) has been studied experimentally in a CO₂ laser plasma interaction. A N₂ gas jet target was irradiated with CO₂ laser light (wavelength, ⋋ = 10.6 µm and frequency, ѡ₀) at intensities up to 10¹⁴ Wcm⁻². SRS occurs at intensities greater than 3 x 10¹³ Wcm⁻², which is fair agreement with threshold predictions for a plasma with an electron temperature of 300eV and a density scale length of 300µm. After this intensity is reached, the plasma waves grow exponentially in time with a growth rate of 6 x 10⁻³ѡ₀. This was measured with ps resolution ruby laser Thomson scattering. Spatial growth was also observed. Scattered infrared light at 2⋋ was found. Weak IR light in a broad band near 15µm was also found. The saturated plasma wave level and the number of hot electrons at 150 keV are well correlated, which indicates that trapping is responsible for the electrons. However, trapping is not responsible for the saturation of the instability. Frequency resolved Thomson scattering revealed that ion acoustic waves start at the peak of the SRS fluctuations. Once the ion acoustic waves grow to a large amplitude, SRS is quenched and does not reappear. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Tunable high order anti-Stokes radiation produced by stimulated Raman scattering in liquid nitrogen is studied experimentally. The light beams of two lasers of different frequencies a ruby laser and tunable dye laser --.are simultaneously focussed in liquid nitrogen and two distinct series of anti-Stokes lines are observed. The dye laser anti-Stokes lines can be changed in frequency by tuning the dye laser. The intensities of the two series of lines are investigated as a function of both ruby and dye laser power, The dye laser anti-Stokes line intensities are found to have a distinct threshold for ruby laser power but no threshold for dye laser power. The experimental results support a two step model in which the ruby laser acts as a pump for molecular vibrations which in turn modulate the dye laser frequency. / Science, Faculty of / Physics and Astronomy, Department of / Graduate