Holographic storage in electrooptic crystals. i. steady state

Kukhtarev, Nickolai V.; Markov, Vladimir B.; Odulov, S. G.; Soskin, M. S.; Vinetskiǐ, V. L.

doi:10.1080/00150197908239450

Cited by 1,645 publications

(384 citation statements)

References 20 publications

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“…Unless stated otherwise, the external writebeam powers were adjusted so that the internal intensities were equal (write-beam ratio b I 2 /I 1 1). This maximizes the contrast m 2(I 1 I 2 ) 1/2 /(I 1 I 2 ) of the interference pattern and thus, according to reference [18], the achievable space ± charge field E SC . The FWHM of the plane Gaussian writing beams was 0.47 mm.…”

Section: Methodsmentioning

confidence: 98%

“…This is partly due to the reduced grating contrast m (Figure 1 B, open symbols), since it directly influences E SC and thus, Dn as mentioned above. [18] However, it is also asymmetrical: for a given contrast a significantly higher Dn was achieved when the preillumination intensity was higher (b < 1). In order to eliminate the influence of the grating contrast on the performance we calculated the quasi steady-state refractive index modulation amplitude Dn from h int using Equation (2 b) and normalized this value using the grating contrast m (Figure 1 C).…”

Section: Nir Preillumination Dependency On Beam Intensity Ratiomentioning

confidence: 99%

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Photophysical and Redox NIR‐Sensitivity Enhancement in Photorefractive Polymer Composites

et al. 2004

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Section: Methodsmentioning

confidence: 98%

Section: Nir Preillumination Dependency On Beam Intensity Ratiomentioning

confidence: 99%

Photophysical and Redox NIR‐Sensitivity Enhancement in Photorefractive Polymer Composites

et al. 2004

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“…The set of equations describing the optical properties of a photorefractive crystal, known as the Kukhtarev equations [26], are…”

Section: Appendix A: Derivation Of Equationsmentioning

confidence: 99%

Two-dimensional modulational instability in photorefractive media

Saffman¹,

McCarthy²,

Królikowski³

2004

J. Opt. B: Quantum Semiclass. Opt.

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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 ...

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“…The solid line is a fit derived from the standard theory of photorefractivity. [34][35][36] Here, the magnitude of the space-charge electric field, |E sc | takes the form where m ) I 1 I 2 /(I 1 + I 2 ) is the modulation depth; E q ) eN pr / ( 0 r K G ) is the trap-density-limited space-charge field, where N pr is the effective trap density, 0 is the permittivity of free space, K G is the grating wave vector, and e is the fundamental unit charge; E d ) k B TK G /e is the diffusion field, where k B is Boltzmann's constant and T is the absolute temperature; and σ p and σ d are photoconductivity and dark conductivity, respectively. Assuming the general condition E d , E 0 , E q is met, Γ can be expressed as …”

Section: Resultsmentioning

confidence: 99%

Inorganic: Organic Hybrid Nanocomposites for Photorefractivity at Communication Wavelengths

et al. 2002

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This paper reports new photorefractive polymeric nanocomposites photosensitized with HgS or PbS nanocrystals and operating at the communication wavelength of 1.3 µm. To our knowledge, it is the first report of a polymeric photorefractive medium with spectral response at a communication wavelength. The nanocomposites involving HgS are prepared by an in-situ nanochemistry approach, whereas those involving PbS were prepared using competitive nanochemistry. Photoconductivity experiments were employed in the characterization of photocharge generation quantum efficiency provided by the semiconductor nanocrystals. The photorefractive nature of the composites is confirmed using electric field dependent two-beam coupling. In the case of nanocomposite containing PbS nanocrystals, a net gain in excess of the associated absorption loss is observed.

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Holographic storage in electrooptic crystals. i. steady state

Cited by 1,645 publications

References 20 publications

Photophysical and Redox NIR‐Sensitivity Enhancement in Photorefractive Polymer Composites

Photophysical and Redox NIR‐Sensitivity Enhancement in Photorefractive Polymer Composites

Two-dimensional modulational instability in photorefractive media

Inorganic: Organic Hybrid Nanocomposites for Photorefractivity at Communication Wavelengths

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