Synopsis: Molecular Memory for Light

Hydrogen molecules act as a fast and efficient memory storage for light pulses.
Synopsis figure
P. J. Bustard et al., Phys. Rev. Lett. (2013)

Quantum processors, like their classical counterparts, will need fast and reliable memories to store and retrieve information as superpositions of states. Researchers are pursuing several photonic technologies, among others, to achieve this by storing quantum information in specially prepared solids, ions, and atomic vapors. Philip Bustard and colleagues at the National Research Council (NRC) of Canada, Ontario, have now investigated another kind of storage medium: the vibrational modes of molecules. Their experiments, published in Physical Review Letters, demonstrate that the system can act as a fast and efficient molecular quantum memory.

Bustard et al. sent 100-femtosecond laser pulses into a cell filled with H2 to map photons onto an ensemble vibrational coherence and read out the photons after a delay time. In the writing process, the laser pulses scatter inelastically from the H2, leaving the molecules in a vibrationally excited state. Reading is achieved by using the pulses to kick the molecules back to the ground state, with the re-emission of the stored photons.

The NRC researchers measured write efficiencies of nearly 30% and readout efficiencies of more than 60%, depending on gas pressure, and they were able to store the photons for as long as a nanosecond. The authors also demonstrated that the memory was coherent and linear, which are essential for a quantum memory. And because the bandwidth of the memory is well matched to existing femtosecond photon sources, the authors hope this proof-of-principle result may lead to fast photon memories capable of fitting on a microchip. The scheme offers a number of advantages over other methods, principally that such photon memories could work at terahertz speed, while alternative schemes are so far mostly limited to the gigahertz regime. – David Voss


Features

More Features »

Announcements

More Announcements »

Subject Areas

Atomic and Molecular PhysicsQuantum Information

Previous Synopsis

Next Synopsis

Related Articles

Focus: New View of Cold Atoms Flowing
Atomic and Molecular Physics

Focus: New View of Cold Atoms Flowing

A new technique produces an image of the flow of cold atoms through a channel, a potentially important tool for future cold-atom technology. Read More »

Viewpoint: Seeing Scrambled Spins
Atomic and Molecular Physics

Viewpoint: Seeing Scrambled Spins

Two experimental groups have taken a step towards observing the “scrambling” of information that occurs as a many-body quantum system thermalizes.   Read More »

Viewpoint: Type-II Dirac Fermions Spotted
Quantum Information

Viewpoint: Type-II Dirac Fermions Spotted

Three separate groups report experimental evidence of novel type-II Dirac quasiparticles, suggesting possible applications in future quantum technology. Read More »

More Articles