Photorefractive solitons

Królikowski, Wiesław; Luther‐Davies, Barry; Denz, Cornélia

doi:10.1109/jqe.2002.806190

Cited by 78 publications

(44 citation statements)

References 139 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…To verify our theoretical findings we conducted experiments using a crystal of photorefractive strontium barium niobate as the nonlinear medium. The experimental setup is analogous to that used in our earlier studies of photorefractive soliton formation [13]. The crystal was 5x5x10 mm in size with the optical beam propagating along the 10 mm axis and a DC electric field of 1.1 kV applied along the 5 mm longĉ-axis.…”

Section: Figmentioning

confidence: 99%

See 1 more Smart Citation

Two-dimensional modulational instability in photorefractive media

Saffman¹,

McCarthy²,

Królikowski³

2004

J. Opt. B: Quantum Semiclass. Opt.

View full text Add to dashboard Cite

We study theoretically and experimentally the modulational instability of broad optical beams in photorefractive nonlinear media. We demonstrate the impact of the anisotropy of the nonlinearity on the growth rate of periodic perturbations. Our findings are confirmed by experimental measurements in a strontium barium niobate photorefractive crystal.PACS numbers: 42.65. Hw, 42.65.Jx A plane wave propagating in a medium with focusing nonlinearity is unstable with respect to the generation of small scale filaments [1]. This so called modulational instability (MI) phenomenon, has been extensively studied because of its importance as a factor limiting the propagation of high power beams. Filamentation may also be identified as the first stage in the development of turbulent fluctuations in the transverse profile of a laser beam [2]. In addition, MI is often considered as a precursor for the formation of spatial and/or temporal optical solitons. As far as optics is concerned, MI has been studied in media with various mechanisms of nonlinear response including cubic [1], quadratic [3], nonlocal [4,5] and inertial [6,7] types of nonlinearity. Importantly, MI is not restricted to nonlinear optics but has also been studied in many other nonlinear systems including fluids [8], plasmas [9] and matter waves [10].In the context of optical beam propagation in nonlinear materials MI has usually been considered in media with spatially isotropic nonlinear properties. Recently a great deal of theoretical and experimental efforts have been devoted to studies of nonlinear optical effects and soliton formation in photorefractive crystals [11,12,13]. While these media exhibit strong nonlinearity at very low optical power their nonlinear response is inherently anisotropic [14]. The anisotropy causes a number of observable effects including astigmatic self-focusing of optical beams [15], elliptically shaped solitary solutions [16], geometry-sensitive interactions of solitons [17], and fixed optical pattern orientation [18].Several previous studies of MI in the context of photorefractive media were limited to a 1-dimensional geometry where the anisotropy is absent [19,20,21], and the physics is similar to the standard saturable nonlinearity [22]. On the other hand, in a real physical situation where one deals with finite sized beams, the anisotropic aspects of the photorefractive nonlinear response are expected to play a significant role. Some previous work [23,24] already indicated the importance of anisotropy in the transversal break-up of broad beams propagating in biased photorefractive crystals. However, no detailed analysis of this phenomenon was carried out. In this paper we study the MI of optical beams in photorefractive media taking into account the full 2-dimensional anisotropic model of the photorefractive nonlinearity.Time independent propagation of an optical beam E(r, z) = (A/2)e ı(kz−ωt) + c.c. in a nonlinear medium with a weakly varying index of refraction is governed by the parabolic equationHere r = (x, y) and z are ...

show abstract

Section: Figmentioning

confidence: 99%

“…Recently a great deal of theoretical and experimental efforts have been devoted to studies of nonlinear optical effects and soliton formation in photorefractive crystals [11,12,13]. While these media exhibit strong nonlinearity at very low optical power their nonlinear response is inherently anisotropic [14].…”

mentioning

confidence: 99%

Two-dimensional modulational instability in photorefractive media

Saffman¹,

McCarthy²,

Królikowski³

2004

J. Opt. B: Quantum Semiclass. Opt.

View full text Add to dashboard Cite

show abstract

“…The experimental set-up is analogous to that used in our earlier studies of photorefractive soliton formation [13]. The crystal was 5 × 5 × 10 mm 3 in size with the optical beam propagating along the 10 mm axis and a DC electric field of 1.1 kV applied along the 5 mm longĉ axis.…”

Section: S399mentioning

confidence: 99%

“…Recently a great deal of theoretical and experimental effort has been devoted to studies of nonlinear optical effects and soliton formation in photorefractive crystals [11][12][13]. While these media exhibit strong nonlinearity at very low optical power, their nonlinear response is inherently anisotropic [14].…”

mentioning

confidence: 99%

Two dimensional modulational instability in photorefractive media

Saffman

McCarthy

Królikowski

2004

Nonlinear Guided Waves and Their Applications

View full text Add to dashboard Cite

We study theoretically and experimentally the modulational instability of broad optical beams in photorefractive nonlinear media. The angular dependence of the growth rate of periodic perturbations is calculated. Our findings are confirmed by experimental measurements on a strontium barium niobate photorefractive crystal.Keywords: photorefractive nonlinear optics, self-focusing, instabilities A plane wave propagating in a medium with focusing nonlinearity is unstable with respect to the generation of small scale filaments [1]. This so-called modulational instability (MI) phenomenon has been extensively studied because of its importance as a factor limiting the propagation of high power beams. Filamentation may also be identified as the first stage in the development of turbulent fluctuations in the transverse profile of a laser beam [2]. In addition, MI is often considered as a precursor for the formation of spatial and/or temporal optical solitons. As far as optics is concerned, MI has been studied in media with various mechanisms of nonlinear response including cubic [1], quadratic [3], nonlocal [4,5] and inertial [6,7] types of nonlinearity. Importantly, MI is not restricted to nonlinear optics but has also been studied in many other nonlinear systems including fluids [8], plasmas [9] and matter waves [10].In the context of optical beam propagation in nonlinear materials MI has usually been considered in media with spatially isotropic nonlinear properties. Recently a great deal of theoretical and experimental effort has been devoted to studies of nonlinear optical effects and soliton formation in photorefractive crystals [11][12][13]. While these media exhibit strong nonlinearity at very low optical power, their nonlinear response is inherently anisotropic [14]. The anisotropy causes a number of observable effects including astigmatic selffocusing of optical beams [15], elliptically shaped solitary solutions [16], geometry-sensitive interactions of solitons [17] and fixed optical pattern orientation [18].Several previous studies of MI in the context of photorefractive media were limited to a one-dimensional geometry where the anisotropy is absent [19][20][21], and the physics is similar to the standard saturable nonlinearity [22]. On the other hand, in a real physical situation where one deals with finite sized beams, the anisotropic aspects of the photorefractive nonlinear response are expected to play a significant role. Some previous work [23,24] already indicated the importance of anisotropy in the transverse breakup of broad beams propagating in biased photorefractive crystals. However, no detailed analysis of this phenomenon was carried out. In this paper we study the MI of optical beams in photorefractive media taking into account the full two-dimensional anisotropic model of the photorefractive nonlinearity.Time independent propagation of an optical beam E(r, z) = (A/2)e i(kz−ωt) + c.c. in a nonlinear medium with a weakly varying index of refraction is governed by the parabolic equationHere r ...

show abstract

“…Spatially nonlocality is a generic property in different materials including the photorefractive media [1,2], thermal nonlinear media [3][4][5][6][7], liquid crystals [8][9][10][11][12][13], and so on. Nonlocality can lead to new kinds of waves that would have been otherwise impossible in local nonlinear media.…”

Section: Introductionmentioning

confidence: 99%

(2+1)D surface solitons at the interface between a linear medium and a nonlocal nonlinear medium

Shi

Guo

2011

J. Opt. Soc. Am. B

View full text Add to dashboard Cite

We address (2+1)D surface solitons occurring at the interface between a linear medium and a nonlocal nonlinear medium whose nonlinear contribution to the refractive index has a initial value at the interface. We find that there exist stable single and dipole surface solitons which do not exhibit a power threshold. The properties of the surface solitons can be affected by the initial value and the degree of nonlocality. When a laser beam is launched away from the interface, the beam will be periodic oscillations.

show abstract

Photorefractive solitons

Abstract: We present a review of recent works on spatial optical solitons in photorefractive media. We discuss fundamental properties of screening solitons and their interaction.

Cited by 78 publications

References 139 publications

Two-dimensional modulational instability in photorefractive media

Two-dimensional modulational instability in photorefractive media

Two dimensional modulational instability in photorefractive media

(2+1)D surface solitons at the interface between a linear medium and a nonlocal nonlinear medium

Contact Info

Product

Resources

About