A Study of Transient Stimulated Raman Scattering and Self-Focusing in the Picosecond Time Regime.
Abstract
The high intensities and short durations available in mode locked laser pulses have made possible the study of optical interactions with matter in entirely new regimes of intensity and time. Because of the large electric fields present in these pulses, third order susceptibilities can determine the dominant optical response of a medium. In addition, the extremely short durations of these pulses causes many nonlinear optical interactions to become transient, since the pulse is over before the medium can fully respond. In this report, a study of two third order processes, Stimulated Raman Scattering and self-focusing, with picosecond pulses is reported. A time of flight technique is used to study the propagation properties of a self-focused beam. These results are compared with recently developed transient theories of the self-focusing process which result from numerical integration of the self-focusing equations for both phase and amplitude. Many of the propagation and spectral properties of the self-focused pulses are successfully accounted for by the transient theory which predicts a region of stabilized duration and diameter in the tail of the pulse which is constant in form over many centimeters in the cell. Finally, the symmetry of experimental spectra is not fully accounted for in the transient theory, and additional explanations of this effect are proposed. The design and construction of a diffraction limited Nd:glass mode locked laser system with reproducible output pulses containing peak intensities of about 10 GW/sq cm is also described. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1971
- Accession Number
- AD0732009
Entities
People
- John F. Reintjes
Organizations
- Harvard University