gradient-echo-quantum-memory-in-warm-atomic-vapor

Gradient Echo Quantum Memory in Warm Atomic Vapor

Gradient  echo memory (GEM) is a protocol for storing optical quantum states of light in  atomic ensembles. The primary motivation for such a technology ...

The Australian National University

Multimode nonclassical states of light are an essential resource in quantum computation with continuous variables, for example, in cluster state computation. We report in this Letter the first experimental evidence of a multimode nonclassical frequency comb in a femtosecond synchronously pumped optical parametric oscillator. In addition to a global reduction of its quantum intensity fluctuations, the system features quantum correlations between different parts of its frequency spectrum. This allows us to show that the frequency comb is composed of several uncorrelated eigenmodes having specific spectral shapes, two of them at least being squeezed, and to characterize their spectral shapes.

Generation and characterization of multimode quantum frequency combs.

We propose a direct and real-time displacement measurement using an optical frequency comb, able to compensate optically for index of refraction variations due to atmospheric parameters. This scheme could be useful for applications requiring stringent precision over a long distance in air, a situation where dispersion becomes the main limitation. The key ingredient is the use of a mode-locked laser as a precise source for multi-wavelength interferometry in a homodyne detection scheme. By shaping temporally the local oscillator, one can directly access the desired parameter (distance variation) while being insensitive to fluctuations induced by parameters of the environment such as pressure, temperature, humidity and CO2 content.

Real-time displacement measurement immune from atmospheric parameters using optical frequency combs.

A method for time differentiation based on a Babinet-Soleil-Bravais compensator is introduced. The complex transfer function of the device is measured using polarization spectral interferometry. Time differentiation of both the pulse field and pulse envelope are demonstrated over a spectral width of about 100 THz with a measured overlap with the objective mode greater than 99.8%. This pulse shaping technique is shown to be perfectly suited to time metrology at the quantum limit.

Olivier Pinel

ARC Centre for Quantum Computation and Communication Technology,
Department of Quantum Science,
ARC Centre for Quantum Computation and Communication Technology, Department of Quantum Science

The Australian National University

Gradient Echo Quantum Memory in Warm Atomic Vapor

Olivier Pinel

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}ARC Centre for Quantum Computation and Communication Technology,Department of Quantum Science,ARC Centre for Quantum Computation and Communication Technology, Department of Quantum Science

The Australian National University

Gradient Echo Quantum Memory in Warm Atomic Vapor

ARC Centre for Quantum Computation and Communication Technology,
Department of Quantum Science,
ARC Centre for Quantum Computation and Communication Technology, Department of Quantum Science