Optical damage thresholds at 2.94 microm in fluoride glass fibers

Area of Science:

• Materials Science
• Optical Engineering
• Laser Physics

Background:

• Fluoride glass fibers are crucial for mid-infrared laser delivery.
• Understanding optical damage thresholds is essential for high-power applications.
• Previous research has not comprehensively evaluated damage in various fluoride fiber types.

Purpose of the Study:

• To determine the optical damage thresholds of single-mode and multimode fluoride glass fibers at 2.94 micrometers.
• To investigate the mechanisms of surface damage induced by high optical power.
• To establish safe power limits for laser transmission through these fibers.

Main Methods:

• Investigated optical damage thresholds using a 2.94 micrometer laser source.
• Tested one single-mode and five multimode fluoride glass fibers with varying core/cladding diameters.
• Analyzed induced surface damage using scanning electron microscopy (SEM).

Main Results:

• Identified distinct damage thresholds for different fluoride glass fiber types.
• SEM analysis revealed specific surface damage morphologies, including micro-cracks and melting.
• Established preliminary power limits for safe laser power delivery.

Conclusions:

• Fluoride glass fibers exhibit varying optical damage resistance based on their structure and composition.
• Surface damage is a critical limiting factor for high-power laser transmission.
• The presented power limits offer guidance for the practical application of these fibers in laser systems.