A frequency multi-mode Tm:LiNbO3 quantum memory

Optical quantum memories require the ability to reversibly map quantum information between photons and atoms [1]. When employed for quantum repeaters, quantum memories are the key to enabling long-distance quantum communication [2]. Quantum memories require recall with high fidelity and efficiency, long storage times, large bandwidth capabilities, and the possibility to store multiple modes for multiplexing [3]. Attractive material candidates for quantum memories, those of rare-earth-ion doped crystals, may serve to simultaneously fulfill all aforementioned requirements [4]. In this presentation, we show how a Tm:LiNbO3 crystal [5, 6] cooled to cryogenic temperatures may serve as an efficient frequency-multiplexed quantum memory. Contrasting previous works that have focused on time-multiplexing [7, 8], we present measurements showing how the wide-band absorption line and large atomic sublevel splitting in Tm:LiNbO3 can be exploited for frequency multiplexing in a quantum repeater. [1] A. I. Lvovsky et. al., Nature Photon. 3, 706 (2009). [2] H.-J. Briegel et al., Phys. Rev. Lett. 81, 5932 (1998). [3] N. Sangouard et al., Rev. Mod. Phys. 83, 33 (2011). [4] W. Tittel et al., Laser Photon. Rev. 4, 244 (2010). [5] E. Saglamyurek et al., Nature (London) 469, 512 (2011). [6] N. Sinclair et al., J. Lumin. 130, 1586 (2010). [7] I. Usmani et al., Nature Commun. 1, 12 (2010). [8] M Bonarota et. al., New J. Phys. 13, 013013 (2011).