Watt-level dysprosium fiber laser at 3.15  μm with 73% slope efficiency

Area of Science:

• Laser Physics
• Materials Science
• Infrared Technology

Background:

• Rare-earth-doped fiber lasers (e.g., erbium, holmium) are key for mid-infrared (mid-IR) generation.
• Existing sources primarily cover 2.6-3.0 μm and 3.3-3.8 μm, leaving intermediate wavelengths underserved.
• This gap limits applications in manufacturing and defense.

Purpose of the Study:

• To investigate dysprosium-doped fiber as a novel gain medium for mid-IR fiber lasers.
• To demonstrate a high-power, efficient fiber laser operating in the underserved 3.15 μm region.
• To explore the potential for power and efficiency scaling.

Main Methods:

• Utilized a simple in-band pumped, grating-stabilized linear fiber laser cavity.
• Employed dysprosium (Dy)-doped fiber as the active gain medium.
• Characterized laser output power and slope efficiency at 3.15 μm.

Main Results:

• Achieved a maximum output power of 1.06 W at 3.15 μm.
• Obtained a slope efficiency of 73% with respect to launched power (77% relative to absorbed power).
• This represents the highest reported efficiency for a mid-IR fiber laser.

Conclusions:

• Dysprosium-doped fiber is a promising material for efficient mid-IR fiber lasers.
• The demonstrated laser addresses the need for sources in the 3.15 μm range.
• Further development could lead to even higher power and efficiency levels for mid-IR applications.