Ultrafast laser damage: the effect of an adhesion layer on damage thresholds

Area of Science:

• Materials Science
• Optics and Photonics
• Surface Science

Background:

• Sub-picosecond laser-induced damage (LID) is a critical factor in the performance and longevity of optical materials.
• Gold films on dielectric substrates exhibit weak adhesion, leading to low damage thresholds characterized by delamination.
• Understanding material properties is essential for predicting and mitigating LID.

Purpose of the Study:

• To investigate the effect of a chromium adhesion layer on the laser-induced damage thresholds of gold films on dielectric substrates.
• To compare the LID response under single-shot and multi-shot laser irradiation conditions.

Main Methods:

• Fabrication of gold films on dielectric substrates with and without an intermediate chromium adhesion layer.
• Characterization of surface morphology and adhesion properties.
• Evaluation of laser-induced damage thresholds using sub-picosecond laser pulses under varying irradiation conditions (single-shot vs. multi-shot).

Main Results:

• The addition of a chromium adhesion layer increased the single-shot laser-induced damage threshold of gold films by a factor of three.
• In contrast, for multi-shot experiments, the chromium layer provided little to no significant increase in the optical damage threshold.
• Delamination was the primary damage mechanism observed at low fluence thresholds.

Conclusions:

• Chromium adhesion layers effectively enhance the resistance of gold films to single-pulse laser-induced damage.
• The protective benefit of chromium layers is significantly reduced under repetitive laser exposure, indicating a need for further investigation into multi-shot damage mechanisms.
• Material adhesion plays a crucial role in laser-induced damage phenomena, particularly in thin film applications.