Nonlinear Self-focusing Medium Research Articles

Imaging and focusing characteristics of partially coherent light pulses focused by a thin lens in nonlinear self-focusing media

For the quasi-steady-state (QSS) self-focusing case, the imaging and focusing characteristics of partially coherent light pulses (PCLPs) propagating through a thin lens in nonlinear self-focusing media are studied. The analytical formulae of the image distance and the image size are derived. It is shown that the time delay of the minimum and maximum of the image distance depends on the light spatial coherence, while the time delay of the maximum of the image size is independent of the light spatial coherence. On the other hand, the analytical formula of the focal length of PCLPs is derived. It is found that, when the value of the pulse peak power is fixed, a PCLP has more advantages to avoid the optical damage of materials as the incident distance or the thin lens focal length increases or the initial pulse width decreases.

ПЕРИОДИЧЕСКИЕ СОСТОЯНИЯ ВБЛИЗИ ПЛОСКОГО ДЕФЕКТА С НЕЛИНЕЙНЫМ ОТКЛИКОМ, РАЗДЕЛЯЮЩЕГО НЕЛИНЕЙНЫЙ САМОФОКУСИРУЮЩИЙ И ЛИНЕЙНЫЙ КРИСТАЛЛЫ

Предложена модель, описывающая особенности распространения возбуждений вблизи границы раздела линейной среды и нелинейной среды с положительной нелинейностью, которая представляет собой плоский дефект с внутренними нелинейными свойствами. В основе модели лежит нелинейное уравнение Шредингера с нелинейным самосогласованным потенциалом. Показано, что в рассматриваемой системе существуют нелинейные пространственно-неоднородные состояния нескольких типов, определяемые различными периодическими решениями нелинейного уравнения Шредингера. Получены и проанализированы дисперсионные соотношения, определяющие энергию таких стационарных состояний. Установлено, что в спектре существуют резонансные состояния, обусловленные исключительно нелинейными свойствами дефекта. Получены добавки к спектральной плотности состояний и указаны ее характерные особенности.

Backward nonlinear surface Tamm states in left-handed metamaterials

We addressed the existence of the nonlinear electromagnetic surface waves, the so-called Tamm states, that form at an interface separating a nonlinear uniform left-handed metamaterial and a conventional one-dimensional photonic crystal. We found two types of nonlinear surface waves, one with a hump at the interface and the other one with two humps. It was demonstrated that the nonlinear metamaterial can support the both type Tamm states with a backward energy flow and allows for a flexible control of the dispersion properties of surface states. We also, described the intensity-dependent properties of surface Tamm states for a nonlinear self-focusing medium.

Biaxial nonlinear surface waves.

In this paper we present calculations describing nonlinear surface waves at the interface between an isotropic nonlinear self-focusing medium and a linear biaxial dielectric. These solutions exhibit self-walk-off in the Poynting vector and elliptical polarization, both of which vary as a function of the distance from the interface. If the dielectric tensor element in the direction perpendicular to the interface has a value that is between the tensor elements in the other two principal directions, then there exists a stop band in the power dispersion curves. This phenomenon is not present when the linear crystal is uniaxial. \textcopyright{} 1996 The American Physical Society.

Pulsed spatial switching at the interface separating Kerr-like instantaneous and relaxing dielectric media.

Propagation of optical pulses, both Gaussian and square in time, at an oblique angle to the interface separating two nonlinear self-focusing media, is studied numerically. The role of a finite-medium response in determining the reflection and transmission asymptotics of the pulse is established, and it is confirmed that, in the limit of a negligible Debye relaxation time, the equivalent particle theory for cw incident beams applies. Examples of spatially distributed multiplexing and demultiplexing of optical pulse trains illustrate the usefulness of the equivalent-particle picture in designing novel optical switching architectures.

Exact Solution for Transverse Electric Polarized Nonlinear Guided Waves in Saturable Media

Abstract The power dependent wave-vector and stationary field distributions for TE polarized nonlinear waves guided by an interface between a linear dielectric and a saturable nonlinear self-focusing medium characterized by the dielectric function ∊ = ∊c + αc¦E¦2 + βc¦E¦4 are exactly calculated. Exact nonlinear wave solutions are also given for TE polarized nonlinear waves guided by dielectric or metallic films bounded on one side by a self-focusing saturable medium characterized by the above dielectric function. The stability on propagation of these nonlinear stationary wave solutions was investigated numerically.

Propagation of a perturbed soliton in nonlinear self-focusing media

A simple method which describes all the stages of propagation is analytically developed for the soliton with a small perturbation in nonlinear self-focusing media. An initial perturbation separates into two waves, one of which has a phase velocity less than that of the soliton and another greater than that of the plane wave in the media without nonlinearity.

TM-type soliton in nonlinear self-focusing media

A soliton of TM type is shown to exist in nonlinear self-focusing media and its propagation characteristics such as field distributions and propagation constant, are clarified and are compared with a soliton of TE type.