15.5 W, pulsed 630 nm generation based on Raman fiber laser and second-harmonic generation.

Area of Science:

• Nonlinear Optics
• Laser Physics
• Materials Science

Background:

• High-power visible light sources are crucial for various scientific and industrial applications.
• Existing methods for generating specific visible wavelengths often face limitations in power, efficiency, or beam quality.
• Efficiently converting near-infrared lasers to visible wavelengths remains a significant challenge in photonics.

Purpose of the Study:

• To demonstrate a novel method for generating high-power, nanosecond 630 nm laser light.
• To investigate the combined use of Raman conversion and second-harmonic generation (SHG) for visible light production.
• To achieve high conversion efficiency and good beam quality at the 630 nm wavelength.

Main Methods:

• Utilized a 116.2 W, 1080 nm single-mode fiber laser as the pump source.
• Employed third-order Raman conversion, seeded by a 1260 nm laser diode, to achieve 63.7 W at 1260 nm with 54.8% efficiency.
• Performed second-harmonic generation (SHG) using a bismuth triborate (BIBO) nonlinear crystal under type-I noncritical phase-matching conditions.

Main Results:

• Generated 63.7 W of optical power at 1260 nm with a Raman conversion efficiency of 54.8%.
• Achieved 15.5 W of average power at 630 nm via SHG.
• Obtained a SHG efficiency of 24.4% with a pulse width of 16.0 ns at a repetition rate of 9.26 MHz.

Conclusions:

• Successfully demonstrated a high-power, nanosecond 630 nm beam generation technique.
• The combined Raman conversion and SHG approach offers a viable route to efficient visible light sources.
• This work facilitates the development of high-power visible light sources with excellent beam quality at specific wavelengths.