Nano-imprint lithography of broad-band and wide-angle antireflective structures for high-power lasers

Area of Science:

• Materials Science
• Optics and Photonics

Background:

• Anti-reflection coatings are crucial for minimizing light loss in optical systems.
• Traditional coatings often struggle with broadband performance, wide angular acceptance, and high laser-induced damage thresholds.

Purpose of the Study:

• To demonstrate efficient anti-reflection coatings utilizing adiabatic index matching.
• To achieve high optical transmission, achromaticity, and wide angular acceptance using nano-imprint lithography.

Main Methods:

• Fabrication of anti-reflection coatings via nano-imprint lithography.
• Characterization of optical properties including transmission, achromaticity, and angular acceptance.
• Evaluation of laser-induced damage thresholds and low absorption.

Main Results:

• Achieved high total transmission (99.5%–99.8% from 390–900 nm, 99%–99.5% from 800–1600 nm).
• Demonstrated wide angular acceptance (T > 99% up to 50 degrees).
• Exhibited high laser-induced damage thresholds (>5 J/cm² in fs, >150 J/cm² in ns regimes) and low absorption (<1.3 ppm).

Conclusions:

• Nano-imprint lithography enables efficient anti-reflection coatings with excellent optical performance.
• The developed coatings meet stringent requirements for high-power laser systems and broadband optical applications.
• Adiabatic index matching provides a viable route to advanced optical coating designs.