Optical Wave Propagation in Kerr Media

2022

The new features of the light localization along the graded-index substrate covered by the cladding characterized by a self-focusing nonlinearity are described theoretically. In the model of nonlinearity the dielectric function in substrate depends linearly on the distance from the cover-substrate interface. The optical characteristics of Kerr type positive nonlinear response in the cover is changed abruptly with an increasing light intensity. The light intensity distribution in across interface direction described by exact solution to nonlinear wave equation is calculated and analyzed. It is found that increasing the width of the graded-index layer leads to a shift in the position of the maximum intensity. The intensity maximum appears in the graded-index substrate after the effective refractive index reaches the critical value. The thickness of nonlinear near-surface layer, which is formed after the light intensity reaches the critical value, monotonically decreases with increasing width of the graded-index layer. The possibility of realizing a multimode regime of the light propagation, which can be realized with an increasing width of the graded-index layer and it is characterized by a deep penetration of the light field into the substrate, is derived. The possibility of control the distribution of the light power between the cover and substrate by change in the effective refractive index and the width of the graded-index layer is described.

Section: Light Intensity Distributionmentioning

confidence: 99%

“…In addition, the linearly graded-index medium makes it possible to reduce the energy losses [13]. Waveguide structures with Kerr nonlinearity are also widespread [14,15], which are used to study the features of the propagation of localized light pulses and solitons [16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Light localization in a linearly graded-index substrate covered by intensity dependent nonlinear self-focusing cladding

2022

“…The typical dependences of domain width (15) are plotted in figure 3. The analysis of (15) shows that the value of z s monotonically increases with increasing n at fixed value of E s , but it monotonically decreases with increasing E s at fixed value of n.…”

Section: The Reduction Of Nonlinear Response In a Self-focusing Mediummentioning

confidence: 99%

“…Nonlinear surface waves have been theoretically studied for a long time [1][2][3][4][5][6][7][8][9][10][11][12]. Authors have used different models of medium nonlinear response in order to describe the various peculiarities of the pulse, soliton and wave propagations in nonlinear optical media [13][14][15][16][17][18][19][20][21][22][23]. However, the description of patterns of nonlinear response controlled by the light intensity requires detailed study.…”

Section: Introductionmentioning

confidence: 99%

The reduction of nonlinear response in near-surface layers by adjusting the electric field amplitude

2021

In this work, we use a special nonlinear dependence of dielectric permittivity to study theoretically the effect of a decrease in the nonlinear response in near-surface layers of a medium, which occurs with an increase in the amplitude of the electric field. We propose a model of nonlinearity in which the Kerr-type nonlinearity abruptly disappears with an increase in the field, and the dielectric permittivity becomes constant and independent of the field. Increasing the electric field leads to the formation of a local zone (optical domain) near the surface with linear optical properties where the dielectric permittivity becomes independent of the electric field. We formulate a nonlinear equation with stepwise dependence of the dielectric permittivity on electric field, and obtain its two types of exact solutions corresponding to the surface waves in media with positive (self-focusing) and negative (defocusing) nonlinear responses. We calculate and analyze the total power flows of thesurface waves of both types. We discuss in detail the features of the obtained solutions in comparison with previously published results. It is shown that the choice of a crystal with an appropriate nonlinear response makes it possible to increase or decrease the field intensity near the crystal surface with practically the same thickness of the near-surface layer with altered optical properties.

“…Surface wave propagation along the interface between crystals with stepwise nonlinearity and linear optic media has been discussed in detail [18][19][20][21][22][23][24]. Similarly, surface waves propagating along interfaces between media with Kerr nonlinearity are well studied [26][27][28][29][30][31][32][33][34][35]. Therefore, in our opinion, it is of interest to describe new types of surface waves with special structures that propagate along the contact of such crystals with predominantly different forms of the dependence of the dielectric constant on the amplitude of the electric field strength.…”

Section: Introductionmentioning

confidence: 99%

Propagation of nonlinear surface waves along the interface between a Kerr-type crystal and a medium characterized by stepwise dielectric permittivity

2020

The contact of a medium characterized by Kerr nonlinearity and a medium characterized by a stepwise nonlinearity, where the dielectric permittivity depends on the amplitude of the electric field strength, is considered. It is found that an optical domain of finite thickness is formed. Two new types of surface waves are described. The influence of the switching field on the intensity distribution across the interface and on total power flow is analyzed. The intensity at the interface in the case of contact with a nonlinear focusing medium can be maximal, in contrast to the case of contact with a linear medium where the intensity at the interface could not be maximal. The total power flow monotonically decreases with an increase in the nonlinearity parameter and it takes the minimum value at a specific value of the switching amplitude. The largest fraction of the power flow is concentrated on the right side of the optical domain for small values of the switching field starting from a certain value.