Laser intensity modulation by nonabsorbing defects [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 1997.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- 10 pages : digital, PDF file
- Additional Creators:
- Lawrence Livermore National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- Nonabsorbing bulk defects can initiate laser damage in transparent materials. Defects such as voids, microcracks and localized stress concentrations can serve as positive or negative lenses for the incident laser light. The resulting interference pattern between refracted and diffracted light can result in intensity increases on the order of a factor of 2 some distance away from a typical negative microlens, and even larger for a positive microlens. Thus, the initial damage site can be physically removed from the defect which initiates damage. The parameter that determines the strength of such lensing is (Ka)²Δε, where the wavenumber K is 2π/λ linear size of the defect and AF, is the difference in dielectric coefficient between matrix and scatterer. Thus, even a small change in refractive index results in a significant effect for a defect large compared to a wavelength. Geometry is also important. Three dimensional (eg. voids) as well as linear and planar (eg. cracks) microlenses can all have strong effects. The present paper evaluates the intensification due to spherical voids and high refractive index inclusions. We wish to particularly draw attention to the very large intensification that can occur at inclusions.
- Report Numbers:
- E 1.99:ucrl-jc--124536-rev.1
E 1.99: conf-9610225--7-rev.1
- Other Subject(s):
- Published through SciTech Connect.
2. annual solid state lasers for applications to inertial confinement fusion (ICF), Paris (France), 22-25 Oct 1996.
Feit, M.D.; Rubenchik, A.M.
- Funding Information:
View MARC record | catkey: 14743508