Ultrafast coherent transients & excited state dynamics in gases and solids

• Main Author: Dawson, Daniel Richard
• Format: Others
• Published: 1978
• Online Access: https://thesis.library.caltech.edu/5398/1/Dawson_dr_1978.pdf; Dawson, Daniel Richard (1978) Ultrafast coherent transients & excited state dynamics in gases and solids. Master's thesis, California Institute of Technology. doi:10.7907/E3GT-JD57. https://resolver.caltech.edu/CaltechTHESIS:11242009-080339920 <https://resolver.caltech.edu/CaltechTHESIS:11242009-080339920>

I. A new technique utilizing the electro-optic frequency switching of a single mode ( 6 Mhz) dye laser was used to observe free induction decay and optical nutation in iodine gas and optical nutation in an organic mixed crystal (pentacene in p-terphenyl) at low temperature. A new technique, incoherent resonance decay (IRO) was also developed. These experiments allow one to determine T_1 and T_2, the longitudinal and transverse relaxation times of the excited ensemble, in analogy with magnetic resonance. For I_2(g) at O∙C; T_l = 2.3 x 10^(-7) sec, T_2 ≃ 1 x 10^(-7) sec. These techniques are limited to a time scale > 10 nsec. II. The construction and characterization of "cw", mode-locked dye laser capable of putting out a continuous train of reproducible sub-picosecond pulses is described. Experiments utilizing this laser for the measurement of picosecond coherent transients and time resolved absorption spectroscopy are proposed.