Highly-Efficient Photon-Atom Quantum Interface Based on Electromagnetically-Induced Transparency

Shengwang Du

Sheng-Jun Yang, Jun Rui, Han-Ning Dai +3 more

Quantum interface of coherent optical field and atomic excitations plays an important role in quantum metrology and quantum information science. The electromagnetically-induced-transparency (EIT) technique has shown versatile and powerful capability in many applications during the last decades. By using efficient EIT-based memory, we directly observed single-photon-level Ramsey interference and also high-contrast spectral transparency comb with a visibility up to about 0.81 at around the resonant line in cold atoms. The interference fringes are mainly influenced by the pulse repetition period, the waveform overlap of the slowed and retrieved signal pulses, and the coherent lifetime of the EIT memory. All these factors have been investigated in detail. Such high-contrast interference fringe may offer us methods for precision measurement and potential applications in areas of atomic clock and magnetometry.

Shuyu Zhou, Shanchao Zhang, Chang Liu +5 more

We report an experimental demonstration of optimal storage and retrieval of heralded single-photon wave packets using electromagnetically induced transparency (EIT) in cold atoms at a high optical depth. We obtain an optimal storage efficiency of (49 ± 3)% for single-photon waveforms with a temporal likeness of 96%. Our result brings the EIT quantum light-matter interface closer to practical quantum information applications.

Shengwang Du

Alex Nemiroski, Philip John Walther, Alexey Vyacheslavovich Gorshkov +2 more

Yi‐Hsin Chen, Meng‐Jung Lee, I-Chung Wang +4 more

A high-storage efficiency and long-live quantum memory for photons is an essential component for the information processing in long-distance quantum communication and optical quantum computation. We demonstrated a 78% storage efficiency (SE) of coherent light pulses with a cold atomic medium based on the effect of electromagnetically induced transparency (EIT). We also obtained a large fractional delay of 74 at 50% SE, which is the best record to date. The measured fidelity of the memory is better than 90%. The results suggest the EIT light-matter interface can be readily applied to single-photon quantum states. Our work greatly advances the technology of EIT-based quantum memory for the practical quantum information applications.