Competition between Raman and Kerr effects in microresonator comb generation

Area of Science:

• Nonlinear optics
• Quantum optics
• Materials science

Background:

• Microresonators are key for generating optical frequency combs.
• Raman and Kerr nonlinear effects play crucial roles in microresonator dynamics.
• Understanding these effects is vital for controlling comb generation.

Purpose of the Study:

• To investigate the interplay of Raman and Kerr gain in crystalline microresonators.
• To determine the conditions necessary for generating mode-locked frequency combs.
• To analyze the impact of Raman gain on microresonator size limitations for comb formation.

Main Methods:

• Theoretical modeling of Raman and Kerr gain effects.
• Experimental verification using diamond and silicon microresonators.
• Analysis of comb states resulting from competing nonlinear phenomena.

Main Results:

• A strong, narrowband Raman gain imposes a maximum size limit on microresonators for comb generation.
• Experimental results in diamond and silicon microresonators confirm this size limitation.
• A competition between Raman and Kerr effects leads to the observation of two distinct frequency comb states.

Conclusions:

• Raman gain is a critical factor in dictating the feasibility of frequency comb generation in microresonators.
• The identified competition between Raman and Kerr effects offers new insights into controlling microresonator-based frequency combs.
• This work provides a pathway for optimizing microresonator design for specific frequency comb applications.