Search results for "Nonlinear"
showing 10 items of 3684 documents
Optomechanical oscillations in microbubble resonators: Enhancement, suppression and chaotic behaviour
2019
We report on the experimental and theoretical analysis of parametrical optomechanical oscillations in hollow spherical PhoXonic whispering gallery mode resonators due to radiation pressure. The optically excited acoustic eigenmodes of the PhoXonic cavity oscillate regeneratively leading to parametric oscillation instabilities.
Modulational instability in resonant optical fiber with higher-order dispersion effect
2010
International audience; The modulational instability (MI) of an electromagnetic wave in a resonant optical fiber with a two-level system is investigated. In the normal dispersion regime, we find the occurrence of nonconventional MI sidebands which are induced by the two-level resonant atoms. We also observe that the MI gain spectra are suppressed by the higher-order dispersion effect in the anomalous dispersion regime.
Linear and nonlinear spin dynamics in multi-domain magnetoelastic antiferromagnets
2021
Antiferromagnets have recently surged as the prominent material platform for the next generation spintronics devices. Despite the remarkable abundance of antiferromagnets and the variety of their spin textures in nature, they share a widely common, if not ubiquitous, feature. Magnetoelasticity, which is expressed as strictions of different origin, relativistic and/or exchange, significantly contributes to the magnetic anisotropy of antiferromagnets. Crucially, a general theoretical framework able to address the role of domain walls on the spin dynamics in antiferromagnets in the presence of magnetoelasticity is lacking. Here we tackle this problem developing a very general macroscopic pheno…
Temporal Soliton “Molecules” in Mode-Locked Lasers: Collisions, Pulsations, and Vibrations
2008
A few years after the discovery of the stable dissipative soliton pairs in passively mode-locked lasers, a large variety of multi-soliton complexes were studied in both experiments and numerical simulations, revealing interesting new behaviors. This chapter focuses on the following three subjects: collisions between dissipative solitons, pulsations of dissipative solitons, and vibrations of soliton pairs. Different outcomes of collisions between a soliton pair and a soliton singlet are discussed, showing possible experimental control in the formation or dissociation of ‘soliton molecules’. Long-period pulsations of single and multiple dissipative solitons are presented as limit cycles and o…
Spectral incoherent solitons
2009
Solitons have been usually considered as inherently coherent localized structures and the discovery of incoherent optical solitons has represented a significant progress [1]. As occurs for standard coherent solitons, incoherent solitons are characterized by a confinement of the field in the spatial or in the temporal domain. We introduce here a novel type of incoherent solitons that are neither spatial nor temporal, i.e., the incoherent field does not exhibit any confinement in the spatiotemporal domain; however, the uncorrelated frequency components that constitute the incoherent field exhibit a localized soliton behavior in the frequency domain [2].
Duty-ratio control of Nonlinear phase noise in dispersion-managed WDM transmissions using RZ-DPSK modulation at 10 Gb/s
2006
International audience; The authors compare analytical and numerical estimates, showing that the nonlinear phase noise of short optical pulses associated with the coupling between amplified spontaneous emission noise and fiber nonlinearity may be controlled by adjusting the duty cycle of the return-to-zero (RZ) signal modulation format. The impact of this effect in the optimization of the performance of 10-Gb/s dispersion-managed wavelength division multiplexed (WDM) systems using RZ-differential phase-shift keying (DPSK) modulation is discussed. By extensive numerical simulations, it is shown that the transmission quality of ultradense WDM systems using the RZ-DPSK modulation format may be…
What is the Right Theory for Anderson Localization of Light? An Experimental Test
2018
Anderson localization of light is traditionally described in analogy to electrons in a random potential. Within this description, the random potential depends on the wavelength of the incident light. For transverse Anderson localization, this leads to the prediction that the distribution of localization lengths---and, hence, its average---strongly depends on the wavelength. In an alternative description, in terms of a spatially fluctuating electric modulus, this is not the case. Here, we report on an experimentum crucis in order to investigate the validity of the two conflicting theories using optical samples exhibiting transverse Anderson localization. We do not find any dependence of the …
Coherent vector pi-pulse in optical amplifiers
2007
We obtain an exact vector solitary solution for the amplification of an optical pulse with a time width short compared with both population and polarization decay time. This dissipative soliton results from the balance between the gain from inverted resonant two-level atoms and the linear loss of the host material. We suppose that the excited state of the active centers is degenerate on the projection of the angular moment. Numerical simulations demonstrate the stability of these vector dissipative solitons in the presence of both linear birefringence and group velocity dispersion of the host material.
Dynamic Stark effect action on optical pumping of atoms in an external magnetic field
1992
Abstract The influence of the dynamic Stark effect on the optical pumping of atoms in a magnetic field, using the broad band approximation, is examined. It is demonstrated that the dynamic Stark effect can lead to a nonlinear effect on the light intensity conversion of alignment produced by linearly polarized light in the orientation of the angular momentum of atoms.
Excitation of E1-forbidden Atomic Transitions with Electric, Magnetic or Mixed Multipolarity in Light Fields Carrying Orbital and Spin Angular Moment…
2019
Photons carrying a well-defined orbital angular momentum have been proven to modify spectroscopic selection rules in atomic matter. Excitation profiles of electric quadrupole transitions have been measured with single trapped $^{40}$Ca$^+$ ions for varying polarizations. We further develop the photo-absorption formalism to study the case of arbitrary alignment of the beam's optical axis with respect to the ion's quantization axis and mixed multipolarity. Thus, predictions for M1-dominated $^{40}Ar^{13+}$, E3-driven $^{171}Yb^+$ and $^{172}Yb^+$, and B-like $^{20}Ne^{5+}$ are presented. The latter case displays novel effects, coming from the presence of a strong photon -- magnetic dipole cou…