Low-threshold CW eye-safe vortex generation from an intracavity pump-wave off-axis pumped OPO

Area of Science:

• Optics and Photonics
• Laser Physics
• Structured Light Generation

Background:

• Generating vortex beams with specific properties is crucial for advanced optical applications.
• Existing methods for vortex generation often require complex setups or high thresholds.
• Efficient and versatile methods for creating structured light are in demand.

Purpose of the Study:

• To propose and demonstrate a low-threshold, efficient setup for continuous-wave (CW) wavelength-versatile vortex generation.
• To utilize an intracavity optical parametric oscillator for achieving low-threshold operation.
• To explore the generation of high-order Hermite-Gaussian modes for subsequent vortex beam formation.

Main Methods:

• Employing an intracavity optical parametric oscillator.
• Utilizing off-axis pumping of the signal-wave oscillator to generate high-order Hermite-Gaussian modes.
• Implementing an astigmatism mode converter to transform Hermite-Gaussian modes into vortex beams.
• Comparing the proposed method with diode off-axis pumping for performance verification.

Main Results:

• Successful generation of high-order Hermite-Gaussian modes in the eye-safe spectral region.
• Demonstration of efficient vortex beam generation using an astigmatism mode converter.
• Verification of superior laser performance compared to the diode off-axis pumping method.
• Achieved low-threshold operation for continuous-wave vortex generation.

Conclusions:

• The proposed intracavity optical parametric oscillator setup offers an efficient and low-threshold approach for versatile vortex generation.
• The off-axis pumping technique effectively produces high-order Hermite-Gaussian modes suitable for vortex beam creation.
• This method shows promise for generating more complex structured light beams in the future.