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

Abstract

Using a nondegenerate four-wave mixing process based on a double-Λ scheme in hot cesium vapor, we generate quantum correlated twin beams with a maximum intensity-difference squeezing of 6.5 dB. The substantially improved squeezing can be mainly attributed to very good frequency and phase-difference stability between the pump and probe beams in our experiment. Intensitydifference squeezing can be observed within a wide experimental parameter range, which guarantees its robust generation. Since this scheme produces multi-spatial-mode twin beams at the Cs D1 line, it is of interest for experiments involving quantum imaging and coherent interfaces between atomic and solid-state systems.

Spiral bandwidth of four-wave mixing in Rb vapour

“…Correlations are also observed in properties other than the transverse mode. Intensitydifference squeezed beams have been generated via FWM in atomic vapours 22 , and intensity correlations have been transferred from one field to another 23 . Similar systems have been used to prepare heralded bichromatic single photons 24 , and polarisation entangled photons have been produced with cold atoms 25 .…”

Compact sub-kilohertz low-frequency quantum light source based on four-wave mixing in cesium vapor

“…Three successive temperature-stabilized etalons (with a thickness of 7 mm, 7 mm, and 3 mm, respectively) are used to select the probe frequency component (−1 st order sideband) from the carrier and two sidebands. It has been shown that the frequency and phase-difference stability between the pump and probe beams is very good with this method [28].…”

“…In the low-frequency region, a squeezed vacuum state with a Fourier frequency down to 100 Hz is generated based on the polarization self-rotation effect in atomic vapor [22]. Recently, it was shown that quantum correlated twin beams can be generated based on the FWM process in a double-Λ scheme in hot rubidium vapor [23][24][25][26][27] and cesium vapor [28]. This system has proven to be very successful for a variety of applications such as the generation of multiple quantum correlated beams [29,30], entangled images [31], high purity single photons [32], as well as optical qubits [33], the tunable delay of EPR entangled states [34], the realization of a SU(1,1) nonlinear interferometer [35], and the ultrasensitive measurement of microcantilever displacement below the shot-noise limit [36].…”

Quantum-Enhanced Two-Photon Spectroscopy Using Two-mode Squeezed Light

“…The highest squeezing has been achieved in PPKTP crystals using frequency down conversion at 1064 nm [37]. Finally, other alkali metals, in particularly cesium, can be explored for FWM intensity squeezing generation [38].…”