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Feedback Enhanced Phonon Lasing of a Microwave Frequency Resonator
preprintposted on 2023-08-22, 16:00 authored by Peyman Parsa, Prasoon Kumar Shandilya, David P. Lake, Matthew E. Mitchell, Paul E. Barclay
The amplitude of self-oscillating mechanical resonators in cavity optomechanical systems is typically limited by nonlinearities arising from the cavity's finite optical bandwidth. We propose and demonstrate a feedback technique for increasing this limit. By modulating the cavity input field with a signal derived from its output intensity, we increase the amplitude of a self-oscillating GHz frequency mechanical resonator by $22\%$ (increase in coherent phonon number of $50\%$) limited only by the achievable optomechanical cooperativity of the system. This technique will advance applications dependent on high dynamic mechanical stress, such as coherent spin-phonon coupling, as well as implementations of sensors based on self-oscillating resonators.