Highly efficient continuous-wave solid-state Raman crystal lasers at 555 and 559 nm.

Area of Science:

• Laser Physics
• Nonlinear Optics
• Solid-State Lasers

Background:

• Continuous-wave (CW) lasers are crucial for various scientific and industrial applications.
• Generating visible light efficiently from near-infrared lasers remains a challenge.
• Raman lasers offer a pathway to wavelength conversion but often suffer from efficiency limitations.

Purpose of the Study:

• To develop high-power, efficient CW Raman lasers operating in the green and lime spectral regions.
• To investigate the use of Np-cut potassium gadolinium tungstate (KGW) for Stokes wave generation.
• To optimize intracavity sum frequency generation (SFG) for visible light production.

Main Methods:

• Utilized a Nd:YVO4/KGW Raman laser system pumped at 1064 nm.
• Employed Np-cut KGW crystals for Stokes wave generation at 1159 nm and 1177 nm.
• Implemented intracavity type-I sum frequency generation in lithium triborate (LBO) crystals for 555 nm and 559 nm output.
• Optimized cavity length and phase matching temperature for maximum conversion efficiency.

Main Results:

• Achieved CW output powers of 6.6 W at 555 nm and 6.3 W at 559 nm with 22 W pump power.
• Attained high conversion efficiencies of up to 30% for 555 nm and 28.6% for 559 nm.
• Demonstrated the effectiveness of a double-sided dichroic coating output coupler in enhancing resonance quality factor.

Conclusions:

• Successfully demonstrated high-power, efficient CW Raman lasers in the green and lime spectral regions.
• The combination of KGW for Stokes generation and LBO for SFG provides a viable route for visible laser development.
• Optimized cavity parameters are critical for achieving high performance in such laser systems.