Subpicosecond Resolved Incipient Laser Damage
Final rept. 15 Mar 1989-31 Mar 1992
CALIFORNIA UNIV IRVINE
Pagination or Media Count:
The overall goal of this line of research is to determine in detail laser induced transient dynamics in condensed matter in the presence of phonons and carriers at concentrations which exceed thermal equilibrium and approach the threshold for incipient damage. Two major problems had to be solved before meaningful data could be obtained and a theoretical basis was achieved with which the observed transient dynamics could be understood. The experimental problem of sufficient signal-to-noise to observe very fast optical transients in the presence of intense laser beams was solved through two unique laser systems. These laser systems consist of dual synchronously pumped and synchronously amplified dye lasers combined with the generation and kiloherz rate amplification of synchronized femtosecond and picosecond laser systems. Also important was the development of fast 1 KHz analogue to digital converter needed to abstract the data and to regulate various components of the laser system. Specifically, this involved the construction of the 1 KHz computerized data acquisition system consisting of before and after sample photodiode beam detection and Raman signal detection, amplification, gated integration and ad conversion. This pulse-by-pulse normalized scheme has been used to investigate the absorption properties of the GaP crystal necessary for this experiment.
- Lasers and Masers