Absolute Two-Photon Absorption Coefficients in UltraViolet Window Materials
Abstract
The absolute two-photon absorption coefficients of u.v. transmitting materials have been measured using well-calibrated single picosecond pulses, at the third and fourth harmonic of a mode locked Nd:YAG laser systems. Two-photon absorption coefficients of the order of .001 cm/MW were measured for alkali- halides, and .0001 cm/MW for harmonic generating crystals. In materials with band gap greater than 2 h-bar omega, no nonlinear absorption could be observed. Calculations based on the Keldysh theory with one adjustable parameter agree quite well with the experimentally observed dispersions in the two-photon absorption coefficients. The effect of multi-photon absorption on the conversion efficiency of harmonic generating crystals and on the breakdown of u. v. window materials is also discussed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1977
- Accession Number
- ADA050379
Entities
People
- J. Blake
- Nicolaas Bloembergen
Organizations
- Harvard University