Persistent dynamics in coupled non-degenerate parametric oscillators: pump saturation prevents mode competition

Area of Science:

• Wave Physics
• Nonlinear Dynamics
• Quantum Optics

Background:

• Coherent dynamics in coupled oscillators are crucial for wave phenomena like energy exchange (beats).
• Active oscillators typically exhibit transient coherent dynamics due to pump saturation and mode competition.
• This saturation usually leads to a single dominant mode, suppressing multi-mode behavior.

Purpose of the Study:

• To investigate the effect of pump saturation on coherent dynamics in coupled parametric oscillators.
• To explore the persistence of multi-mode dynamics and coherent beats under saturation.
• To understand the underlying mechanisms preventing synchronization in saturated coupled oscillators.

Main Methods:

• Experimental realization of two coupled parametric oscillators using frequency modes within a single radio frequency (RF) cavity.
• Arbitrary coupling achieved using a digital high-bandwidth Field-Programmable Gate Array (FPGA).
• Numerical simulations to analyze the interplay of pump depletion and oscillator dynamics.

Main Results:

• Observed persistent coherent beats in coupled parametric oscillators, maintained at all pump levels, even far above threshold.
• Demonstrated that pump saturation counter-intuitively preserves multi-mode dynamics, contrary to expectations for active oscillators.
• Simulations revealed that pump depletion between oscillators prevents synchronization, even under deep saturation.

Conclusions:

• Coupled parametric oscillators exhibit sustained coherent dynamics and beats due to pump saturation, challenging conventional understanding.
• The interplay of pump depletion is key to preventing synchronization and maintaining multi-mode behavior.
• This finding opens new avenues for controlling and utilizing coherent dynamics in nonlinear systems.