We report that the optical gain and intensity difference squeezing (IDS) of four-wave mixing can be controlled using an external dressing field in a hot rubidium atomic system. The intensity of the parametric amplified four-wave mixing (PA-FWM) signal in the probe and corresponding conjugate channels can be enhanced using the dressed effect, resulting in an increase of the optical gain. So, the IDS in the dressed PA-FWM has a higher degree of −7.1 dB, as compared to that in the PA-FWM of −2.5 dB. This scheme of enhancing the optical gain and the generated IDS requires a simple experimental setup that is mechanically stable. These outcomes can be used in the fabrication of quantum devices and the realization of quantum metrology.

We study the parametric amplification of electromagnetically induced transparency-assisted Rydberg six-and eight-wave mixing signals through a cascaded nonlinear optical process in a hot rubidium atomic ensemble both theoretically and experimentally. The shift of the resonant frequency (induced by the Rydberg-Rydberg interaction) of parametrically amplified six-wave mixing signal is observed. Moreover, the interplays between the dressing effects and Rydberg-Rydberg interactions in parametrically amplified multiwave mixing signals are investigated. The linear amplification of Rydberg multiwave mixing processes with multichannel nature acts against the suppression caused by Rydberg-Rydberg interaction and dressing effect.

In this paper, we demonstrate that the intensity difference squeezing (IDS) of parametric amplified four-wave mixing (PA-FWM) can be modulated by the phase-sensitive dressed effect in a hot rubidium (Rb) atomic system. The introduction of phase-sensitive dressed effect can enhance the degree of IDS of PA-FWM to −8.1 dB, as compared to that in the phaseinsensitive dressed PA-FWM of −6.6 dB. The phase-sensitive dressing field can not only enhance the degree of IDS of PA-FWM by the dressed effect, but can also be treated as the seed beam of the PA-six wave mixing process. So, double-injected three-mode IDS obviously has a bigger degree of IDS compared with the single-injection case. One advantage of the current scheme for enhancing the generated IDS is that the experimental setup is simple and mechanically stable. These outcomes can be used in the fabrication of quantum devices and the realization of quantum metrology.

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The non-classical states of light serve as a potential candidate for emerging quantum information process. A processing trend to enhance its scalability is to integrate multiple nonlinear processes with the dressed-state picture into a single device, and therefore, are useful for quantum computations. Here, a novel method is proposed to experimentally achieve the generation of coexisting two pairs of narrow-band biphotons by two four-wave mixing processes in a single hot rubidium vapor cell. Based on the photon-atom nonlinear interfaces, the generated biphotons exhibits genuine entanglement in time-energy. Meanwhile, the nonlinear susceptibility with the dressed-state picture decides the temporal correlation of the biphotons wave packet as a damped periodic Rabi oscillation, suggesting the property of the high-dimensional time-energy entangled state. Such a high-dimensional entangled state also is an efficient way to enhance information carrying capacity. By alternating two nonlinear susceptibilities in a single device, respectively, there exists a competition of the generation rate between such two pairs of biphotons. Moreover, both generated two pairs of biphotons that violate the Cauchy-Schwarz inequality and show their non-classical behavior.