Influence of Antireflection Si coatings on the Damage Threshold of fused silica upon irradiation with Mid-IR femtosecond laser pulses

TL;DR

This study investigates how antireflection silicon coatings affect the damage threshold of fused silica when irradiated with mid-infrared femtosecond laser pulses, revealing thickness-dependent optical properties that influence damage susceptibility.

Contribution

It introduces a simulation-based analysis of how Si/SiO2 coating thickness modulates reflectivity, transmissivity, and damage threshold under mid-IR femtosecond laser irradiation.

Findings

Reflectivity and transmissivity depend on coating thickness.

Coating thickness influences the damage threshold.

Simulation results guide material selection for coatings.

Abstract

Recent progress in the development of high-power mid-IR laser sources and the exciting laser driven physical phenomena associated with the irradiation of solids via ultrashort laser pulses in that spectral region are aimed to potentially create novel capabilities for material processing. In particularly, the investigation of the underlying physical processes and the evaluation of the optical breakdown threshold (OBT) following irradiation of bulk dielectric materials with Mid-IR femtosecond (fs) pulses has been recently presented. In this report, we will explore the conditions that generate sufficient carrier excitation levels which leads to damage upon irradiated a dielectric material (SiO2) coated with antireflection (AR) semiconducting films (Si) of variable thickness with fs pulses. Simulation results demonstrate that the reflectivity and transmissivity of the Si/SiO2 are thickness-dependent which can be employed to modulate the damage threshold of the substrate. The study is to provide innovative routes for selecting material sizes that can be used for antireflection coatings and applications in the Mid-IR region.