Quantum Optics Seminar: Dr. Liu Yulong

SiC-based microwave cavity optomechanical devices: slow-light and quantum storage

Crystalline silicon carbide (SiC) has served as a vital industrial material for over a century, with diverse applications in high-power electronics, high-temperature sensors, and biosensing devices. In this talk, we will explore the remarkable potential of cubic silicon carbide (3C-SiC) crystals in developing high-quality mechanical oscillators and their implications for enhancing long-lived phononic memories, functional repeaters, and high-efficiency transducers. We will demonstrate the exceptional compatibility of high-stress crystalline 3C-SiC membranes with superconducting microwave circuits. The phenomenon of degeneracy breaking is revealed, and multiple long-lived phononic mode pairs are observed, with Q-factors exceeding 10⁸. This achievement sets a new record, representing a two-order-of-magnitude improvement for mechanical resonators made from crystalline silicon carbide. Another significant advantage of 3C-SiC is its remarkable stability in mechanical frequency, which results in a tunable group delay with maximum slow-light times extending up to an hour. Sideband cooling operations, along with a coherent electromechanical interface, enable precise control of long-lived phonons, facilitating the on-demand storage and retrieval of microwave coherent states. These advancements mark significant progress at the intersection of materials science, micro-electromechanical systems, and hybrid quantum technologies.