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a Time evolution of a continuous-wave probe field at the exit of the medium n = 20/a under the variation of the relative phase /(s). b The relative phase /(s) versus time is a cosine-type wave ranged from 0 to p/2: /ðsÞ ¼ 0:25p cosð2pf sÞ þ 0:25p: Other parameters are X p ¼ 0:2c 31 ; X c ¼ 4c 31 ; X m ¼ 1:5c 31 ; f ¼ 0:05c 31 ; D p ¼ 0; D c ¼ 0; c 21 ¼ c 31 ; and c 23 dph = 0.01c 31 , respectively
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We study phase-controlled absorption-gain and dynamic switching behaviors in a nanodiamond nitrogen-vacancy (NV) center. The NV center is driven coherently by a weak probe laser field, a control laser field and a microwave field. To describe the transient behavior of the system, we go beyond the steady-state approximation and simultaneously solve t...
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Citations
... Particularly in the atomic configuration of quantum loop schemes, the relative phase can modify dramatically the linear and nonlinear optical properties. This leads to some interesting phenomena, e.g., phase control of EIT [29,30], amplification without inversion [31], phasesensitive atom localization [32], giant Kerr nonlinearity associated with self-phase modulation and cross-phase modulation [6,[33][34][35], transient behavior [36,37], and optical switching and other phase-dependent coherent properties [38][39][40][41][42][43][44][45]. The studies show that the closed-loop configuration is phase-sensitive to quantum coherent controls. ...
... Thus, it delivers more control modes in optical switching. It is worth mentioning here that these works focused only on the stationary-state response of the medium, although the dynamical response is fundamental for the optical switching [35,42]. Growing from this interest, in this work we propose to use a closed-loop three-level lambda system excited by a pump and probe optical fields together with a microwave for the generation of optical switching. ...
... In the following, we solved the coupled Bloch-Maxwell equations (2a)-(2g) on a space-time grid by a combination of the four-order Runge-Kutta and finite difference methods for the initial condition at which all atoms are in the ground state |1〉, and for the boundary condition at which the initial probe field is a continuous wave (cw) at the entrance of the medium. We used the relative phase f(τ) to inform a nearly square wave with smooth rising and falling edges in four ranges: 0 to π/2, π/2 to π, π to 3π/2, and 3π/2 to 2π [42]: Here, a n =1, 2, 3, and 4, corresponding to the ranges 0-π/2, π/2-π, π-3π/2, and 3π/2-2π, respectively. Figure 3 shows a switching process of the probe field at ξ=50/α inside the medium, where the probe transmission is switched to a nearly square pulse train depending on the switching range of the relative phase. ...
We propose a model for optical switching in a closed-loop three-level lambda atomic system excited by two optical fields, coupling and probe lights, and by a microwave driven field. A set of coupled Maxwell-Bloch equations for the atom-field system is numerically solved with a combination of the Runge-Kutta and finite difference techniques. It is shown that the transmitted probe light can be switched to a nearly-square pulse train by switching the relative phase of the interacting fields or by switching the intensity of the microwave field. Furthermore, the switching mode between the probe field and relative phase can be anti-synchronous or synchronous depending on the relative phase modulated to /2 and 3/2 or and 2, respectively. Also, the efficiency and rate of the switching can be controlled by the microwave field, the relative phase and intensity of the coupling field. Such a controllable optical switching model can be applied in the design of optical switching and amplification devices working at low light intensities.
In this paper, we study the spatially structured optical effects that occur when weak laser lights interact with coherently prepared semiconductor quantum dots (SQDs). Initially, the SQD is prepared in a coherent superposition of the lower exciton states. By utilizing two weak optical vortex fields that couple to a biexciton state, we observe spatially dependent effects of the absorption of probe fields. Using the well-established Maxwell–Bloch equations, we analyze the generation of composite optical vortex beams within this system. Our investigation revolves around the formation of different types of spatially dependent beams, exploring their properties and characteristics. Additionally, the transfer of optical vortices through the parametric generation process is examined, for the case where only one vortex beam is present at the beginning of the medium. This study provides insights into the spatially structured optical phenomena in coherently prepared SQDs and contributes to the understanding of light–matter interactions in such systems.
Controllable all-optical switching by relative phase and spontaneously generated coherence in a three-level Λ-type atomic system is our aim in this study. We have generated a near-square probe pulse train with a similar modulation period through periodic modulation of the relative phase or coupling field intensity. Results show that the spontaneously generated coherence and phase range have a strong influence on the efficiency and shape of the switching pulse. Furthermore, the phase switching performance is enhanced as spontaneously generated coherence increases with incoherent pumping. In addition, synchronous or asynchronous switching of the probe pulse is observed in different phase domains (0–π or π–2π). The studied scheme may be helpful for use in the design of optical switching devices in optical communications.Graphical abstractPulse propagation in the EIT medium.
The article reports the C-nitro functionalization of hydroxyl-terminated natural rubber (HTNR) by nitration with nitryl-iodide agent over the HTNR backbone, resulting in the formation of a conjugated nitro-alkene derivative of HNTR (N-HTNR). The reaction was carried out with sodium nitrite and iodine. The structure of N-HTNR was approved by FTIR, 1H-NMR, and 13C-NMR. The thermal degradation was determined by TGA. The spectral methods show the presence of nitro-alkene groups in the chain of N-HNNR and no change of the other structure of the HTNR chain. The N-HTNR has good thermal stability for practical applications. The kinetic parameters for the degradation of N-HTNR were obtained from non-isothermal TGA.
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A scheme of optical four-level pulse amplitude modulation (PAM-4) is proposed based on phase-dependent electromagnetic-induced transparency (EIT) in nitrogen-vacancy (NV) centers. For a closed structure, its transmission depends on the relative phase of applied fields. Based on EIT, the PAM-4 may be achieved by encoding the relative phase and decoding the amplitude of the transmission field. Simulation results show that the differential nonlinearity and the integral nonlinearity of the proposed scheme could be reduced by two orders of magnitude compared with that based on Mach–Zehnder modulator scheme, and the ratio of level separation mismatch is closer to the ideal value 1. Furthermore, the improvement of the system at different probe field detunings and coupling field strengths is investigated.
The world of biomedical research is in constant evolution, requiring more and more conditions and norms through pre-clinic and clinic studies. Nanodiamonds (NDs) with exceptional optical, thermal and mechanical properties emerged on the global scientific scene and recently gained more attention in biomedicine and bioanalysis fields. Many problematics have been deliberated to better understand their in vitro and in vivo efficiency and compatibility. Light was shed on their synthesis, modification and purification steps, as well as particle size and surface properties in order to find the most suitable operating conditions. In this review, we present the latest advances of NDs use in bioapplications. A large variety of subjects including anticancer and antimicrobial systems, wound healing and tissue engineering management tools, but also bioimaging and labeling probes are tackled. The key information resulting from these recent works were evidenced to make an overview of the potential features of NDs, with a special look on emerging therapeutic and diagnosis combinations.
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We have investigated the optical bistability and optical multistability behaviors in a unidirectional ring cavity filled with diamond nitrogen-vacancy (defect centers driven by an elliptically polarized probe field in the presence of magnetic field and compare its properties with the corresponding closed system. Our numerical result demonstrates that threshold of optical bistability and the width of hysteresis loop can be manipulated by adjusting the phase difference between the two circularly polarized components of a single coherent field and cavity parameters, i.e., the electronic exit rate from cavity and electron injection rates. It is also shown that optical bistability and optical multistability are very sensitive to the relative phase between applied fields and magnetic field. It can be realized that by tuning the parameters the transition from bistability to multistability or vice versa can be obtained.
In this paper, two atomic models are proposed in an 35 nm Er3+-doped YAG crystal. The effect of Er3+ ion concentration and incoherent pumping field on optical bistability is discussed. The results for two models show that the threshold of optical bistability for some Er3+ concentration reduces and for some concentration increases. We display that the incoherent pumping field makes the behavior of optical bistability for two proposed model completely different at identical conditions for Er3+ concentration. Our results show that in the absence and presence of incoherent pumping field some Er3+ concentration can lead to maximum and minimum OB threshold. We hope that our proposed model can be suitable for optimizing and controlling the optical bistability in Er3+:YAG crystal.
