Femtosecond excited-state absorption dynamics and optical limiting in fullerene solutions, sol-gel glasses, and thin films
- Los Alamos National Lab., NM (United States)
- Univ. of California, Santa Barbara, CA (United States); and others
We compare detailed dynamics of the excited-state absorption for C{sub 60} in solution, thin films, and entrapped in an inorganic sol-gel glass matrix. Our results demonstrate that the microscopic morphology of the C{sub 60} molecule plays a crucial role in determining the relaxation dynamics. This is a key factor for applications in optical limiting for nanosecond pulses using reverse saturable absorption. We find that the dynamics of the C{sub 60}-glass composite occur on long (ns) timescales, comparable to that in solution; thin film samples, by contrast, show rapid decay (<20 picoseconds). These results demonstrate that the C{sub 60}-sol-gel glass composites contain C{sub 60} in a molecular dispersion, and are suitable candidates for solid-state optical limiting. Multispectral analysis of the decay dynamics in solution allows accurate determination of both the intersystem crossing time (600 {+-}100 ps) and the relative strengths of the singlet and triplet excited-state cross sections as a function of wavelength from 450-950 nm. The triplet excited-state cross section is greater than that for the singlet excited-state over the range from 620-810 nm.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 390629
- Report Number(s):
- LA-UR-96-3197; CONF-960848-20; ON: DE96014926; TRN: 96:005994
- Resource Relation:
- Conference: Denver `96: 1. conference on space processing of materials, at SPIE International Society for Optical Engineering (SPIE) annual international symposium on optical science, engineering, and instrumentation, Denver, CO (United States), 4-9 Aug 1996; Other Information: PBD: 1996
- Country of Publication:
- United States
- Language:
- English
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