arXiv subjects

Chunbai Wu

Publications and source records attributed to Chunbai Wu.

3 recordsLinked to original sources

arXiv2010

Quantum-Fluctuation-Initiated Coherence in Multi-Octave Raman Optical Frequency Combs

We show experimentally and theoretically that the spectral components of a multi-octave frequency comb spontaneously created by stimulated Raman scattering in a hydrogen-filled hollow-core photonic crystal fiber exhibit strong self coherence and mutual coherence within each 12 ns driving laser pulse. This coherence arises in spite of the field's initiation being from quantum zero-point fluctuations, which causes each spectral component to show large phase and energy fluctuations. This points to the possibility of an optical frequency comb with nonclassical correlations between all comb lines.

quant-ph↗

arXiv2007

Mesoscopic entanglement of atomic ensembles through non-resonant stimulated Raman scattering

We propose a scheme of generating and verifying mesoscopic-level entanglement between two atomic ensembles using non-resonant stimulated Raman scattering. Entanglement can be generated by direct detection or balanced homodyne detection of the Stokes fields from the two cells, after they interfere on a beam splitter. The entanglement of the collective atomic fields can be transferred to the anti-Stokes fields in a readout process. By measuring the operator moments of the anti-Stokes fields, we can verify the presence of entanglement. We model the effects of practical factors such as Stokes field detector quantum efficiency and additive thermal noise in the entanglement generating process, and anti-Stokes field losses in the entanglement verification process, and find achievable regimes in which entanglement can be verified at the levels of tens to hundreds of atomic excitations in the ensembles.

quant-ph↗

arXiv2006

Slow Light Propagation in a Linear-Response Three-Level Atomic Vapor

We observe pulse delays of up to twenty times the input pulse duration when 200-ps laser pulses pass through a hot Rb 85 vapor cell. The pulse peak travels with a velocity equal to c/20, and the energy transmission is 5%. For pulses with linewidth greater than typical features in the atomic dispersion, pulse delay is predicted and observed for all center frequencies near resonance. Pulse advance is never observed. The measurements are in good agreement with a three-level linear-dispersion calculation. We are able to control the amount of delay by using a steady-state laser beam for optical pumping of the ground states prior to sending in the test pulse.

physics.optics↗