Experimental investigation of high-frequency-difference twin beams in hot cesium atoms

Abstract

We experimentally investigate the quantum-correlated twin beams generated through stimulated nondegenerate four-wave mixing in the double-lambda atomic system. A 2.5-dB noise reduction of intensity difference with 18.4-GHz frequency difference at the cesium D 1 line is observed in a Cs vapor cell. The quantitative theoretical analysis reveals the experimental difficulty in getting high quantum correlation in Cs atoms because of the large hyperfine splitting of the ground states. However, it is favorable for obtaining quantum correlation in a wide range of pump detunings and relative long lengths of vapor cells. This quantum correlation provides a potential resource for possible coherent interfaces between atomic and solid-state systems due to its wavelength at the Cs D 1 line which lies well within the wavelength regime of the exciton emission from InAs quantum dots.

Squeezed-twin-beam generation in strongly absorbing media

“…We note that these 4WM schemes often allow for a simpler implementation than parametric down conversion in nonlinear crystals, since large values of squeezing can be obtained without the use of a cavity, periodic poling, or waveguide techniques. Similar results have been obtained using cesium atoms [15]. These two systems share the property that the ground state hyperfine splitting is resolved at operating temperatures.…”

Overcoming classical measurement limits through entanglement in photon number: an introduction

“…4WM is a nonlinear phenomenon in optical media with third order susceptibility χ (3) . It can be generated when an intense laser beam (the pump) and a weak laser beam (the seed) overlap in a χ (3) medium (in our case cesium vapor [24]), with frequencies close to resonance with the relevant atomic transitions. The interest for this type of source to generate twin beams has been renewed recently.…”

Generating quantum correlated twin beams by four-wave mixing in hot cesium vapor

“…Cesium offers certain advantages, e.g., the quantum correlation at the 133 Cs D 1 line lies well within the wavelength regime of the exciton emission from InAs quantum dots [34], which provides a potential resource for coherent interfaces between atomic and solid-state systems. The highest degree of intensitydifference squeezing of twin beams based on the FWM process in hot cesium vapor is 2.5 dB [31]. In Ref.…”

“…In Ref. [31], the authors pointed out the experimental difficulty in getting high quantum correlation in cesium vapor because of larger hyperfine splitting of the ground states compared with Rb, as well as experimental limitations such as laser frequency stability, the vapor cell's transmission efficiency, and mechanical vibration of the system. In this paper, we substantially improve the squeezing to 6.5 dB, which can be mainly attributed to very good frequency and phase-difference stability between the pump 6S F=3 and probe beams in our experiment.…”