Optimal detuning for writing warm-atomic-vapor quantum memory in the presence of collisional fluorescence and four-wave mixing

Igor Vurgaftman; Mark Bashkansky

doi:10.1117/12.2004239

Translator Disclaimer

29 March 2013 Optimal detuning for writing warm-atomic-vapor quantum memory in the presence of collisional fluorescence and four-wave mixing

Igor Vurgaftman, Mark Bashkansky

Author Affiliations +

Proceedings Volume 8635, Advances in Photonics of Quantum Computing, Memory, and Communication VI; 86350Q (2013) https://doi.org/10.1117/12.2004239
Event: SPIE OPTO, 2013, San Francisco, California, United States

Abstract

Atomic vapor cells with buffer gas have a number of advantages when employed as quantum memory blocks based on the DLCZ (Duan-Lukin-Cirac-Zoller) protocol: operation slightly above room temperature, ease of handling, as well as commercial availability. Nevertheless, the signal-to-noise ratio in the current implementations is severely limited by the simultaneous presence of collisional fluorescence and the four-wave mixing noise. In our previous work, we have shown how to minimize the influence of the former on the writing process and provided an unambiguous demonstration of quantum memory lasting for 4 μs. An elegant approach to suppress the four-wave-mixing noise by pre-pumping to the state with the hyperfine sublevel with the maximum value was proposed by Walther et al., Int. J. Quantum Inform. 5, 51 (2007). Here we show that this approach is fundamentally limited by the cancellation of the Raman matrix elements involving the Fˊ= 1 and Fˊ= 2 levels, which occurs for all experimental conditions in the S → P transitions of all alkali atoms. A detuning that maximizes the signal-to-noise ratio is shown to exist for a given detector dark-count rate.

Citation Download Citation

Igor Vurgaftman and Mark Bashkansky "Optimal detuning for writing warm-atomic-vapor quantum memory in the presence of collisional fluorescence and four-wave mixing", Proc. SPIE 8635, Advances in Photonics of Quantum Computing, Memory, and Communication VI, 86350Q (29 March 2013); https://doi.org/10.1117/12.2004239

ACCESS THE FULL ARTICLE