High-power wavelength converters with feedback

Area of Science:

• Nonlinear optics
• Laser physics
• Materials science

Background:

• High-peak-power lasers require efficient wavelength conversion for various applications.
• Traditional wavelength converters often face limitations in efficiency and stability.
• Optimizing feedback mechanisms is crucial for enhancing conversion processes.

Purpose of the Study:

• To investigate the theoretical and experimental feasibility of achieving high conversion efficiencies in high-peak-power wavelength converters using small amounts of feedback.
• To explore the impact of radially varying reflectivity profiles on conversion efficiency.
• To demonstrate the practical application of this concept in second-harmonic generation and optical parametric oscillation.

Main Methods:

• Theoretical modeling of wavelength conversion processes with feedback.
• Experimental implementation using deuterated potassium dihydrogen phosphate (DKDP) crystals for second-harmonic generation.
• Experimental implementation using beta-barium borate (BBO) crystals for optical parametric oscillation.
• Comparison of experimental results with simulation data.

Main Results:

• Achieved very high conversion efficiencies in high-peak-power wavelength converters with minimal feedback.
• Demonstrated that maximum efficiencies are obtained with radially varying reflectivity profiles.
• Experimentally obtained 70% energy conversion efficiency in DKDP for second-harmonic generation.
• Obtained 56% energy conversion efficiency in BBO for optical parametric oscillation, consistent with simulations.

Conclusions:

• Small amounts of feedback can significantly enhance conversion efficiencies in high-peak-power wavelength converters.
• Radially varying reflectivity profiles are key to maximizing performance.
• The demonstrated methods are effective and validated by experimental results in nonlinear optical crystals.