Full-bandwidth quantum memory of squeezed light

Achieving high end-to-end efficiency and broadband quantum memory of squeezed light is crucial for continuous-variable quantum information processing. Existing demonstrations fail to store squeezed states across their full squeezing bandwidth. Here, we present a full-bandwidth quantum memory of squeezed light with up to 24 MHz bandwidth, which is at least 12 times that of previous narrowband resonant memory systems, via a far-off resonant Raman process. We achieve output squeezing as high as 1.0±0.29dB, with fidelity above 92±0.5% and a memory efficiency of 80%, corresponding to an end-to-end efficiency of 64.2±0.7% when input squeezing is 1.6±0.23dB. The lowest excess noise of 0.025 shot-noise unit in the memory system is estimated by the noisy model, which benefits from optimizing quantum memory performance with a backward-retrieval strategy. Our results show high-performance memory for squeezed states within tens of MHz-level bandwidth, which has potential applications in high-speed quantum information processing.