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In this paper, the general Langevin equations of motion for the polystyrene bead linked to the lambda-phage worm-like chain DNA molecule embedded in the fluid under the nonlinear optical tweezers is derived in 3D space. Using the finite difference method, the dynamical properties of the bead trapped by the nonlinear optical tweezers using a thin layer of Acid Blue 29 are numerically studied. Results in, the stretched length of the lambda-phage worm-like chain DNA molecule can be controlled in 3D space by finely tuning of the laser power.

Kerr nonlinear coupler consists of two nonlinear oscillations in which one of them linearly excited by an external classical field. This is assumed to be decomposed into two parts: a coherent part and a randomly fluctuating chaotic component that is a δ-correlated, Gaussian, Markov, stationary process (white noise). We solve a set of coupled stochastic integro-differential equations involved in the problem with all initial conditions and obtain analytical formulae for the complex probability amplitudes of finite n-photon Fock states. Especially, our study shows that the system is also able to generate maximally entangled states and, as a consequence, the coupler discussed behaves as a two-qubit system and the results compared with those derived previously in the literature.

In this work, we use method of the operator projection to study in detail the influence of phonon confinement, which depicted in the Huang-Zhu models, Ridley’s guided, and Fuchs–Kliewer slab on the optically detected electrophonon resonance (ODEPR) effect and ODEPR linewidth in square quantum wells. In addition, the ODEPR linewidths the same as functions of the width of well and temperature are also achieved. By numerical calculations for quantum well of the GaAs, we can see that the linewidth reduces with respect to the width of the well and raises with temperature for the cases of bulk and confined phonons. Moreover, we cannot ignore the important role of the influence of phonon confinement in the narrow area of the width of well ( $$L_{z} < 10$$ nm), when considering the ODEPR linewidths.

In this paper, a photonic crystal fiber (PCF) with core infiltrated with Nitrobenzene is proposed and investigated. Its feature properties as the effective refractive index, effective mode area, chromatic dispersion, and confinement loss have been numerically simulated. The obtained results show that characteristic quantities of PCF with core infiltrated with Nitrobenzene (PCF-N) having some advantages in comparison to PCF with core infiltrated with Toluene (PCF-T) at 1.55μm wavelength. For the purpose of supercontinuum generation, two optimal structures with lattice constants 2.0μm and 2.5μm with filling factors d/Ʌ = 0.3 are identified.

The appearance of microlenses in the amorphous crystal Ge33As12Se33 modulated by the acoustic waves with intensity of 107 W/m2 and frequency of (200–400) MHz is presented. The flexibility of microlens, i.e. the dependence of its focal point in 3D space on the parameters of acoustic wave is studied. Basing on flexibility of microlens, a model of acousto-optical tweezers to stretch the λ-phage WLC DNA molecule is proposed. And then the control process of stretched length of DNA molecule in 3D space of the water (fluid) by calibration of the acoustic frequency is numerically observed and discussed. The obtained results show the possibility to use the acousto-optical tweezers to control the stretched length of WLC DNA molecule with high fineness.

The approximate expressions describing the redistribution of laser beam and optical forces in Kerr fluid, and the ratio of refractive indexes basing on the optical Kerr effect in fluid are derived. Basing on them, the dynamic of nonlinear bead in the nonlinear fluid is simulated by the finite different Langevin equation in presence of the optical Kerr and self-focused effects. The radial and axial control processes of bead linking to λ-phage WLC DNA molecule in fluid space are numerically observed by calibration of the laser power under and upper the critical value, respectively. The stable position-laser power characteristics are numerically found out. Based on the results, a sample of single-beam optical tweezers for 3D (axial and radial) control of bead is proposed and discussed.

We consider Raman ring laser by modeling the laser pump light by a classical time-dependent random process, namely a pre-Gaussian process. It is composed of a finite number of independent so-called telegraphs. The strength of the pre-Gaussian formalism derives from the exact solubility of wide classes of the stochastic equations. In particular we also observed the so-called noise reduction in Raman ring laser: the Stokes output of this laser tends to the stabilize under the influence of the broad-band one-telegraph pre-Gaussian pump (Cao Long and Doan Quoc in Opt Quant Electron 43:137–145, 2012). We extend our model to the case of two-telegraph pre-Gaussian noise and compare obtained results with that obtained in our previous paper for the case of broad-band one-telegraph pre-Gaussian pump.

In this paper, we consider the influence of collisional fluctuations on optical phenomena. The fluctuations are taken into account by a simple shift of the constant detuning, involved in a set of optical Bloch equations by collision frequency noise in which this noise is modelled by a two-step random telegraph signal. Following that, the stochastic Bloch equations can be solved analytically in an exact way. As an example, we consider in detail the Mollow spectrum of resonance fluorescence for the case of an arbitrary detuning of the laser frequency, where velocity of the emitters simply has a deterministic value or is distributed with the Maxwell–Boltzmann density in which volume of the buffer gas is arbitrary.

In this paper, we consider the model of a nonlinear system subjected simultaneously to a random telegraph noise and a white noise. By using the formulae of differentiation introduced by Shapiro and Loginov (Physica 91:563–574, 1978), an exact equation for the steady state probability distribution of fluctuation in this system is derived. As an example of its application, we calculate analytically the steady state probability distribution of fluctuation and show the existence of noise induced phase transitions (Wodkiewicz et al. in J. Opt. Soc. Am. 1:398–405, 1984a) in Raman Ring Laser. Moreover, we show explicitly the so-called noise reduction considered in Lewenstein and Rzązewski (Opt. Commun. 63:174–178, 1987) for this system. It follows that the Stokes output of this laser tends to the stabilization under influence of the broad-band telegraph pump. This phenomenon could be realized experimentally in a much easer manner than for the case of Gaussian pump, because the construction of the injected telegraph pump signal is much easer than in the case of Gaussian signal. The recent paper is an extended version of Doan and Van (1991).