Selective Excitation of Coupled Resonators via Complex Frequency Driving: Enhanced Efficiency and Crosstalk Suppression

Abstract: Controlling individual elements of coupled resonator systems poses a significant challenge, as conventional real-frequency pulses suffer from inefficiency and crosstalk, limiting fidelity and scalability. To address this challenge, we propose and explore the use of complex frequency excitations, tailoring the driving signal waveform to match the target complex reflection zeros. We demonstrate that complex frequency driving can achieve near-unity selected energy storage efficiency (100%) in a single resonator, substantially exceeding the performance of optimized Gaussian pulses (~80%). In a coupled three-resonator system, our method yields significantly higher efficiency (92-95%) along with vastly improved selectivity and crosstalk suppression compared to conventional Gaussian pulse excitations of the same duration. Our technique achieves dynamic critical coupling, providing a powerful paradigm for high-fidelity, selective control, crucial for advancing scalable complex systems for sensing and computing.