Spatial rogue waves in the actively Q-switched Nd:YAG laser under low Kerr nonlinearity

Area of Science:

• Laser physics
• Nonlinear optics
• Wave phenomena

Background:

• Spatial rogue waves are rare, high-amplitude optical events.
• Their formation mechanisms, particularly in lasers, are not fully understood.
• Previous studies often linked rogue waves to strong nonlinear effects like self-focusing.

Purpose of the Study:

• To investigate the generation of spatial rogue waves in an actively Q-switched Nd:YAG laser.
• To identify the primary physical mechanisms responsible for their formation.
• To explore the spatio-temporal and coherence characteristics of these rogue waves.

Main Methods:

• Utilized an actively Q-switched Nd:YAG laser system.
• Operated the laser in a low-power regime below the self-focusing threshold.
• Analyzed lasing behavior involving a large number of high-order transverse modes.
• Investigated spatio-temporal dynamics and coherence properties.

Main Results:

• Successfully generated spatial rogue waves in the Nd:YAG laser.
• Observed rogue wave emergence in a low-power regime with numerous high-order transverse modes.
• Demonstrated that modal overlap is the key mechanism for rogue wave generation.
• Showed that significant Kerr nonlinearity is not essential for their formation.

Conclusions:

• Modal overlap is identified as the critical factor for spatial rogue wave generation in this laser system.
• Spatial rogue waves can form without relying on large Kerr nonlinearity or self-focusing.
• The findings offer new insights into rogue wave dynamics in lasers operating with multiple transverse modes.