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Journal ArticleDOI

Observation of self-diffraction effect in acid blue 7 dye soaked gelatin films

01 May 2001-Journal of Modern Optics (Taylor & Francis Group)-Vol. 48, Iss: 6, pp 947-958
TL;DR: In this paper, permanent self-diffraction gratings are formed in red sensitive acid blue 7 dye soaked gelatin films under illumination of an interference pattern by two linearly polarized beams from a He-Ne laser at 632.8 nm.
Abstract: Permanent self-diffraction gratings are formed in red sensitive Acid blue 7 dye soaked gelatin films under illumination of an interference pattern by two linearly polarized beams from a He-Ne laser at 632.8 nm. Growth of the self-diffraction grating is monitored by measuring intensities of various diffraction orders. Systematic studies are carried out to investigate the influence of various parameters involved in diffraction efficiency of the grating such as time of exposure, concentration of dye in the gelatin-coated plate, intensity of interfering beams and intensity ratio of interfering beams. Efficient gratings with ten diffracted orders are formed. Several interesting observations are made by blocking one of the writing beams and an attempt is made to analyse these results.
Citations
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Journal ArticleDOI
TL;DR: In this article, a degenerate four-wave mixing (DFWM) based optical phase-conjugation (OPC) was studied in a few triphenylmethane dye-doped gelatin films using a 633nm He-Ne laser radiation of total power 35mW.

11 citations

Journal ArticleDOI
TL;DR: In this paper, a new series of eosin dye based poly(alkyloxymethacrylate)s was synthesized with an even number of side-chain methylene spacers by a free radical addition polymerization method for holographic optical data storage applications.

4 citations

References
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Journal ArticleDOI
TL;DR: In this paper, a coupled wave analysis of the Bragg diffraction of light by thick hologram gratings is given, analogous to Phariseau's treatment of acoustic gratings and to the dynamical theory of X-ray diffraction.
Abstract: A coupled wave analysis is given of the Bragg diffraction of light by thick hologram gratings, which is analogous to Phariseau's treatment of acoustic gratings and to the “dynamical” theory of X-ray diffraction. The theory remains valid for large diffraction efficiencies where the incident wave is strongly depleted. It is applied to transmission holograms and to reflection holograms. Spatial modulations of both the refractive index and the absorption constant are allowed for. The effects of loss in the grating and of slanted fringes are also considered. Algebraic formulas and their numerical evaluations are given for the diffraction efficiencies and the angular and wavelength sensitivities of the various hologram types.

5,244 citations

Book
03 Jul 1986
TL;DR: Degenerate four-wave mixing (DFWM) as mentioned in this paper is a simple method to achieve phase conjugation, i.e. to generate a wave which propagates time reversed with respect to an incident wave.
Abstract: The invention ofthe laser 25years ago resulted in powerfullight sources which led to the observation of unexpected and striking phenomena. New fields of science such as holography and nonlinear optics developed constituting the basis of this volume. The classical principle of linear superposition of light wavesdoes not hold anymore. Two laser beams crossing in a suitable material may produce a set of new beams with different directions and frequencies. The interaction of light waves can be understood by considering the optical grating structures which develop in the overlap region. The optical properties of matter become spatially modulated in the interference region of two light waves. Permanent holographic gratings have been produced in this way by photographic processes for many years. In contrast, dynamic or transient gratings disappear after the inducing light source, usually a laser, has been switched off. The grating amplitude is controlled by the light intensity. Dynamic gratings have been induced in a large number ofsolids, liquids, and gases, and are detected by diffraction, 'forced light scattering' of a third probing beam, or by self-diffraction of the light waves inducing the grating. The combined interference and diffraction effect corresponds to four-wave mixing (FWM) in the language of nonlinear optics. The process is called degenerate ifthe frequenciesofthe three incident wavesand the scattered wave are equal. Degenerate four-wave mixing (DFWM) is a simple method to achieve phase conjugation, i.e. to generate a wave which propagates time reversed with respect to an incident wave.

1,054 citations

Journal ArticleDOI
TL;DR: In this article, a review of the present state of theoretical and experimental work on the interaction of two coherent light beams of equal frequency in a nonlinear medium is given, and it is shown that dynamic self-diffraction is substantially different for media with different types of response.
Abstract: A review is given of the present state of theoretical and experimental work on the interaction of two coherent light beams of equal frequency in a nonlinear medium. It is shown that dynamic self-diffraction is substantially different for media with different types of response. Stationary energy transfer between interacting beams is possible in the case of nonlocal nonsymmetric response, whereas this type of transfer is forbidden in the case of local response. Different mechanisms for self-induced changes in the refractive index are examined together with the corresponding processes of energy transfer between the writing beams. The more important applications of dynamic self-diffraction are discussed.

191 citations

Journal ArticleDOI
TL;DR: In this article, the origins and dynamics of optical nonlinearities in nematic liquid crystal films, namely, laser-induced molecular reorientational and thermal refractive index changes, are analyzed in the context of optical wave mixings.
Abstract: The origins and the dynamics of optical nonlinearities in nematic liquid crystal films, namely, laser-induced molecular reorientational and thermal refractive index changes, are analyzed in the context of optical wave mixings. Theoretical expressions for the basic non-linearities, the rise and decay time, diffraction efficiencies, and other pertinent parameters involved in the dynamic grating formation are derived. Experimental results obtained with visible and infrared laser pulses are analyzed. Some newly observed novel nonlinear processes are also reported.

39 citations

Journal ArticleDOI
TL;DR: In this paper, steady-state dark spot formation in the center of the far field of a divergent Gaussian beam transmitted through a thin absorbing defocusing liquid medium is reported.

38 citations