Modulational instability of optical beams in photovoltaic and photorefractive media due to two-photon photorefractive effect under open circuit condition

• Published in: Optics communications 2008-12, Vol.281 (23), p.5864-5869
• Main Authors: Hong, W.P., Shwetanshumala, S., Konar, S.
• Format: Article
• Language: English
• Subjects: Dynamics of nonlinear optical systems; optical instabilities, optical chaos and complexity, and optical spatio-temporal dynamics; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Modulational instability; Nonlinear optics; Numerical simulation; Optical materials; Optical solitons; nonlinear guided waves; Optics; Other nonlinear optical materials; photorefractive and semiconductor materials; Phase conjugation, optical mixing; photorefractive and kerr effects; Photovoltaic photorefractive crystal; Physics; Spatial soliton
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2008.08.020

The modulational instability of broad optical beams in two-photon photorefractive (PR) photovoltaic materials under open circuit conditions has been investigated. Under linear stability framework, the one dimensional modulational instability growth rate has been estimated by considering the space charge field. Gain of the instability is shown to exist only when the photovoltaic fields orients in the same direction with respect to the optical c-axis of the medium. It is found that the behavior of the gain spectrum is different in low and high power regions. We have found by numerical simulations that the evolution of the soliton induced by the modulational instability at low photovoltaic field show the dynamical behaviors similar to those of the localized beam as the initial profile. However, it has been shown that increasing photovoltaic fields produce traveling, breathing, and mutually interacting solitons.