Accession Number:

ADA050379

Title:

Absolute Two-Photon Absorption Coefficients in UltraViolet Window Materials

Descriptive Note:

Final technical rept. 1 Jun 1975-30 Sep 1977

Corporate Author:

HARVARD UNIV CAMBRIDGE MA DIV OF APPLIED SCIENCES

Personal Author(s):

Report Date:

1977-12-01

Pagination or Media Count:

51.0

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 NdYAG laser systems. Two-photon absorption coefficients of the order of .001 cmMW were measured for alkali- halides, and .0001 cmMW 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

Subject Categories:

  • Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE