Abstract

A simple and sensitive mode-mismatched thermal lens (TL) technique with a pulsed top-hat beam excitation and a near-field detection scheme is developed to measure in situ the thermoelastic and the thermooptical responses of ultraviolet (UV) dielectric coatings as well as bulk materials under excimer laser (193- or 248-nm) irradiations. Owing to its high sensitivity, the TL technique can be used for measurements at fluences far below the laser-induced damage threshold (LIDT). We report on the measurement of both linear and nonlinear absorption of the UV dielectric coatings and bulk materials as well as the investigation of time-resolved predamage phenomena, such as laser conditioning of highly reflective dielectric coatings and irradiation-induced changes of a coating’s various properties. The pulsed TL technique is also a convenient technique for accurate measurement of the LIDT of dielectric coatings and for distinguishing different damage mechanisms: thermal-stress-induced damage or melting-induced damage.

© 2000 Optical Society of America

Pulsed top-hat beam thermal-lens measurement for ultraviolet dielectric coatings

Bincheng Li, Sven Martin, and Eberhard Welsch
Opt. Lett. 24(20) 1398-1400 (1999)

Combined laser calorimetry and photothermal technique for absorption measurement of optical coatings

Bincheng Li, Holger Blaschke, and Detlev Ristau
Appl. Opt. 45(23) 5827-5831 (2006)

Probe-beam diffraction in a pulsed top-hat beam thermal lens with a mode-mismatched configuration

Bincheng Li and Eberhard Welsch
Appl. Opt. 38(24) 5241-5249 (1999)

Photothermal measurements on optical thin films

E. Welsch and D. Ristau
Appl. Opt. 34(31) 7239-7253 (1995)

Laser conditioning of LaF₃/MgF₂ dielectric coatings at 248 nm

E. Eva, K. Mann, N. Kaiser, B. Anton, R. Henking, D. Ristau, P. Weissbrodt, D. Mademann, L. Raupach, and E. Hacker
Appl. Opt. 35(28) 5613-5619 (1996)