Deterministic generation of bright polarization squeezed state of light resonant with the rubidium D1 absorption line

Abstract

A polarization squeezed optical beam can directly interact with the atomic medium, and its measurement is localoscillator free. Here we have deterministically generated polarization squeezed light at 795 nm. First, a laser at 398 nm is produced from second-harmonic generation with an enhancement cavity. Then a pair of quadrature amplitude squeezed optical fields is prepared with two degenerate optical parameter amplifiers that are pumped by the resulting laser at 398 nm. Finally, the polarization squeezed state of light is generated by combining the above two quadrature amplitude squeezed optical beams on a polarizing beam splitter, and the quantum fluctuations of three Stokes operators simultaneously are reduced 4.0 dB below the quantum noise limit. The polarization squeezing has potential applications in future quantum information networks.

Generation of polarization squeezed light with an optical parametric amplifier at 795 nm

“…Although the squeezing degree is a little bit lower compared with Wu et al's work [26] , the experimental system is greatly simplified. This polarization squeezed light at Rb D 1 line has huge potential in precise measurement of magnetic field.…”

“…Compared with results base on PSR effect of atomic ensemble, the generated polarization squeezed light with this scheme has the advantage of good tenability and higher squeezing degree. In 2006, Wu et al [26] generated -4.0 dB of polarization squeezed light at 795 nm by combining two quadrature amplitude squeezed optical beams on a polarization beam splitter (PBS) cube. This is the maximum polarization squeezing observed at this wavelength.…”

Quantum Entanglement Among Multiple Memories for Continuous Variables

“…Thus the polarization squeezed state of light resonant with rubidium atom D1 absorption has been generated based on sub‐threshold OPAs and beam splitting network. [ 42 ] The operator can be considered as the sum of the mean value and the variance. Two quadrature amplitude squeezed optical modes with the same power and orthogonal polarization are coupled on a PBS with zero phase difference.…”

“…Figure shows the schematic of generating polarization squeezed optical mode. [ 42 ] A Ti:Sapphire laser outputs 795 nm laser, which is used to be the fundamental wave of external cavity enhanced second harmonic genetation (SHG), input signal optical modes of two OPAs and two strong coherent states of optical modes. The 398 nm laser generated by external cavity enhanced SHG is used to pump two identical OPAs for generating two beams of 795 nm quadrature squeezed state of optical modes.…”

“…[ 41 ] Together with the optical beam splitter network, the well understood optical parametric amplifiers (OPAs) have been used to generate CV polarization squeezed state resonant with rubidium atomic absorption line, whose quantum noises of three Stokes operators are all −4.0 dB below QNL. [ 42 ] The bipartite CV polarization entanglement has been theoretically proposed and experimentally investigated. [ 35,43–45 ] With the development of quantum network, the multipartite CV polarization entanglement is required for the multiple users in quantum network, which can transfer quantum state between quantum nodes in quantum network, and the direct interaction between atomic spin waves and polarization components of optical modes.…”