Quantum memory is a key element for quantum repeaters and linear optical quantum computers. In addition to memory, repeaters and computers also require manipulating quantum states by means of unitary transformations, which is generally accomplished using interferometric optical setups. We experimentally investigate photon-echo type atom-light interaction for the possibility to combine storage with controlled transformation of quantum states. As an example, we demonstrate unambiguous state discrimination of qubits and qutrits in an Ti:Er:LiNbO $_3$ waveguide cooled to 3K using states encoded into large ensembles of identically prepared photons in superposition of different temporal modes. The high robustness and flexibility of our approach makes it promising for quantum communication and computation as well as precision measurements.Quantum memory is a key element for quantum repeaters and linear optical quantum computers. In addition to memory, repeaters and computers also require manipulating quantum states by means of unitary transformations, which is generally accomplished using interferometric optical setups. We experimentally investigate photon-echo type atom-light interaction for the possibility to combine storage with controlled transformation of quantum states. As an example, we demonstrate unambiguous state discrimination of qubits and qutrits in an Ti:Er:LiNbO$_3$ waveguide cooled to 3K using states encoded into large ensembles of identically prepared photons in superposition of different temporal modes. The high robustness and flexibility of our approach makes it promising for quantum communication and computation as well as precision measurements.

arXiv:0910.2457Oct 13, 20091 citation

Photon echo quantum memory and state transformation

Ahdiyeh Delfan Abazari, Cecilia La Mela, Wolfgang Tittel

A recently proposed, photon echo related approach to quantum state storage in atomic ensembles employs controlled reversible inhomogeneous broadening (CRIB). Beyond storage, a modified version of CRIB promises controlled quantum state manipulations. As the implementation of CRIB is currently still challenging, we investigate state transformation based on stimulated photon echoes. Specifically, we show how to translate an all optical, beamsplitter based setup into a photon echo based setup, and we simulate a photon echo based POVM (positive operator valued measure) measurement using Maxwell-Bloch equations.A recently proposed, photon echo related approach to quantum state storage in atomic ensembles employs controlled reversible inhomogeneous broadening (CRIB). Beyond storage, a modified version of CRIB promises controlled quantum state manipulations. As the implementation of CRIB is currently still challenging, we investigate state transformation based on stimulated photon echoes. Specifically, we show how to translate an all optical, beamsplitter based setup into a photon echo based setup, and we simulate a photon echo based POVM (positive operator valued measure) measurement using Maxwell-Bloch equations.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEJan 8, 20082 citations

Photon‐echo quantum memory in solid state systems

Wolfgang Tittel, Mikael Afzelius, T. Chanelière +4 more

Abstract Many applications of quantum communication crucially depend on reversible transfer of quantum states between light and matter. Motivated by rapid recent developments in theory and experiment, we review research related to quantum memory based on a photon‐echo approach in solid state material with emphasis on use in a quantum repeater. After introducing quantum communication, the quantum repeater concept, and properties of a quantum memory required to be useful in a quantum repeater, we describe the historical development from spin echoes, discovered in 1950, to photon‐echo quantum memory. We present a simple theoretical description of the ideal protocol, and comment on the impact of a non‐ideal realization on its quantum nature. We extensively discuss rare‐earth‐ion doped crystals and glasses as material candidates, elaborate on traditional photon‐echo experiments as a test‐bed for quantum state storage, and describe the current state‐of‐the‐art of photon‐echo quantum memory. Finally, we give a brief outlook on current research.Abstract Many applications of quantum communication crucially depend on reversible transfer of quantum states between light and matter. Motivated by rapid recent developments in theory and experiment, we review research related to quantum memory based on a photon‐echo approach in solid state material with emphasis on use in a quantum repeater. After introducing quantum communication, the quantum repeater concept, and properties of a quantum memory required to be useful in a quantum repeater, we describe the historical development from spin echoes, discovered in 1950, to photon‐echo quantum memory. We present a simple theoretical description of the ideal protocol, and comment on the impact of a non‐ideal realization on its quantum nature. We extensively discuss rare‐earth‐ion doped crystals and glasses as material candidates, elaborate on traditional photon‐echo experiments as a test‐bed for quantum state storage, and describe the current state‐of‐the‐art of photon‐echo quantum memory. Finally, we give a brief outlook on current research.

Laser & Photonics ReviewMar 23, 2009444 citations

Photon echo memory:principles and applications

Masaharu Mitsunaga

OYOBUTURIJan 1, 19910 citations

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waveguide cooled to 3K using states encoded into large ensembles of identically prepared photons in superposition of different temporal modes. The high robustness and flexibility of our approach makes it promising for quantum communication and computation as well as precision measurements.