High power continuous laser at 461 nm based on a compact and high-efficiency frequency-doubling linear cavity

Area of Science:

• Atomic, Molecular, and Optical Physics
• Laser Physics and Photonics

Background:

• Developing stable, high-power continuous-wave (CW) lasers is crucial for atomic physics applications.
• Frequency conversion techniques are essential for accessing specific wavelengths not readily available from direct laser sources.

Purpose of the Study:

• To generate a Watt-level, single-frequency blue laser at 461 nm.
• To characterize the performance and stability of the generated blue laser.
• To demonstrate the laser's utility in magneto-optical trapping of strontium atoms.

Main Methods:

• Frequency-doubling of a 922 nm amplified diode laser using a lithium triborate (LBO) crystal.
• Employing a resonant Fabry-Pérot cavity to enhance the second-harmonic generation (SHG) efficiency.
• Characterizing laser power stability, residual intensity noise, linewidth, and beam geometry.

Main Results:

• Achieved over 1 W of CW blue laser output power at 461 nm.
• Reached a maximum optical conversion efficiency of 87%.
• Demonstrated a narrow linewidth (approx. 1 MHz) and good long-term power stability.
• Successfully used the blue laser for magneto-optical trapping of 88Sr atoms.

Conclusions:

• The developed frequency-doubling system provides a robust and efficient method for generating high-power blue laser light.
• The laser's performance is suitable for precision atomic physics experiments, including laser cooling and trapping.
• The system shows potential for further power scaling with advancements in fiber amplifiers.