Speaker: Dr. Ying-Cheng Chen

               Institute of Atomic and Molecular Sciences, Academia  Sinica

Time: 5/25, 1:20 p.m, 5/25

Place: meet.google.com/fjm-wgyh-vrn (AMO Seminar 20200525)

Title:  Quantum storage and manipulation of heralded single photons in atomic memories 

Abstract: 
Optical quantum memory is an important component in the long-distance quantum  
communication based on quantum repeater protocol. To outperform the direct  
transmission of light with quantum repeaters, it is crucial to develop quantum  
memories with a high fidelity, high efficiency, high bandwidth and long storage  
time. We demonstrate the storage and manipulation of heralded single photons  
generated from cavity-enhanced spontaneous parametric downconversion (SPDC) in the  
atomic memory based on electromagnetically induced transparency (EIT). We show that  
nonclassical correlations are preserved between the heralding and the retrieved  
photons after storage process. We further demonstrate that the waveform or  
bandwidth, as well as the nonclassical correlation of the single photons can be  
manipulated. We have achieved a memory efficiency of 36% and 80% for cesium EIT  
system operated at D2 line and D1 line, respectively. Our results can be scaled up  
with ease and thus lay the foundation for future realization of large-scale  
applications in quantum information processing.