Generation of squeezed light by an N-configuration atom

E. Giacobino

M. Zhang, Melissa A. Guidry, R. Nicholas Lanning +4 more

We study a squeezed vacuum field generated in hot Rb vapor via the polarization self-rotation effect. Our previous experiments showed that the amount of observed squeezing may be limited by the contamination of the squeezed vacuum output with higher-order spatial modes, also generated inside the cell. Here, we demonstrate that the squeezing can be improved by making the light interact several times with a less dense atomic ensemble. With optimization of some parameters we can achieve up to $\ensuremath{-}2.6$ dB of squeezing in the multipass case, which is a 0.6 dB improvement compared to the single-pass experimental configuration. Our results show that, other than the optical depth of the medium, the spatial mode structure and the cell configuration also affect the squeezing level.

Emil V. Denning, Andreas Knorr, Florian Katsch +1 more

Nonlinear optical effects such as four-wave mixing and generation of squeezed light are ubiquitous in optical devices and light sources. For new devices operating at low optical power, the resonant nonlinearity arising from the two-photon sensitive bound biexciton in a semiconductor microcavity is an interesting prospective platform. Due to the particularly strong Coulomb interaction in atomically thin semiconductors, these materials have strongly bound biexcitons and operate in the visible frequency range of the electromagnetic spectrum. To remove the strong pump laser from the generated light in optical devices or to simultaneously excite nondegenerate polaritons, a bichromatic-pump configuration with two spectrally separated pump lasers is desirable. In this paper, we theoretically investigate spontaneous four-wave mixing and quadrature-squeezing in a bichromatically pumped atomically thin semiconductor microcavity. We explore two different configurations that support degenerate and nondegenerate scattering from polaritons into bound biexcitons, respectively. We find that these configurations lead to the generation of strongly single- and two-mode quadrature-squeezed light.

Eyob Alebachew, K. Fesseha

Gennady A. Koganov, A. M. Khazanoy, R. Shuker

Saesun Kim, Alberto M. Marino

Squeezed states of light have received renewed attention due to their applicability to quantum-enhanced sensing. To take full advantage of their reduced noise properties to enhance atomic-based sensors, it is necessary to generate narrowband near or on atomic resonance single-mode squeezed states of light. We have previously generated bright two-mode squeezed states of light, or twin beams, that can be tuned to resonance with the D1 line of Rb87 with a non-degenerate four-wave-mixing process in a double-lambda configuration in a Rb85 vapor cell. Here, we report on the use of feedforward to transfer the amplitude quantum correlations present in the twin beams to a single beam for the generation of single-mode amplitude squeezed light. With this technique, we obtain a single-mode squeezed state with −2.9±0.1 dB of squeezing when tuned off resonance and −2.0±0.1 dB when tuned on resonance with the D1 F=2 to F′=2 transition of Rb87.