Femtosecond dynamics of highly excited dielectric thin films

Joachim Zeller; Ali J. Sabbah; Mark Mero; Paul M Alsing; John McIver; Wolfgang G. Rudolph

doi:10.1117/12.524456

10 June 2004 Femtosecond dynamics of highly excited dielectric thin films

Joachim Zeller, Ali J. Sabbah, Mark Mero, Paul M Alsing, John McIver, Wolfgang G. Rudolph

Proceedings Volume 5273, Laser-Induced Damage in Optical Materials: 2003; (2004) https://doi.org/10.1117/12.524456
Event: XXXV Annual Symposium on Optical Materials for High Power Lasers: Boulder Damage Symposium, 2003, Boulder, Colorado, United States

Abstract

The dielectric constant of several oxide dielectric thin-films (TiO₂, Ta₂O₅ and HfO₂) excited close to the laser-induced damage threshold is retrieved from reflection and transmission measurements with a 40-fs time resolution. The experiments were compared with the results of a numerical solution of the coupled Boltzmann equations for conduction band electrons and phonons, including nonlinear carrier excitation and relaxation processes as well as defect formation. The observed fast sub-100-femtosecond decay is shown to be caused by the interaction of non-equilibrium electrons with phonons and is in qualitative agreement with the results of the computer simulation. The observed sign reversal of the real part of the dielectric function from negative to positive after several hundred femtoseconds is attributed to the formation of self-trapped excitons (STE's) in the forbidden bandgap. Both real and imaginary part of the dielectric function are successfully modeled with the Boltzmann equation when defect formation is included. The simulations show that STE formation leads to efficient, non-thermal excitation of phonon modes on a sub-picosecond time scale.

Citation Download Citation

Joachim Zeller, Ali J. Sabbah, Mark Mero, Paul M Alsing, John McIver, and Wolfgang G. Rudolph "Femtosecond dynamics of highly excited dielectric thin films", Proc. SPIE 5273, Laser-Induced Damage in Optical Materials: 2003, (10 June 2004); https://doi.org/10.1117/12.524456

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available