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Er'el Granot

Bio: Er'el Granot is an academic researcher from Ariel University. The author has contributed to research in topics: Dispersion (optics) & Brillouin scattering. The author has an hindex of 15, co-authored 132 publications receiving 801 citations. Previous affiliations of Er'el Granot include Israel Atomic Energy Commission & Tel Aviv University.


Papers
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Journal ArticleDOI
Er'el Granot, Aner Lev, Zvi Kotler, Bruno Sfez, Haim Taitelbaum1 
TL;DR: An analytical formula is derived relating the position of the ultrasound transducer and the optical signal at the detector and shows that in certain conditions this ratio is only slowly decreasing as a function of the light penetration depth, which makes this technique attractive for optical tomography.
Abstract: Ultrasound modulated light for optical tomography is very useful, since it can provide three-dimensional data with minimal mathematical processing. Although several experimental studies have shown the potential of this method, the link between the ultrasound location and the modulated signal intensity at the detector is not yet fully understood. We derive an analytical formula relating the position of the ultrasound transducer and the optical signal at the detector. We also derive an expression for the signal-to-shot-noise ratio as a function of the transducer position. We show that in certain conditions this ratio is only slowly decreasing as a function of the light penetration depth, which makes this technique attractive for optical tomography.

49 citations

Patent
23 Jan 2002
TL;DR: In this paper, a method and processing device are presented for reconstructing an absorption and/or scattering image of a region of interest inside a scattering medium, where a mathematical model is provided being representative of a relation between the distribution of the intensity and phase of electromagnetic radiation components scattered from a medium and a certain attenuation factor, which is function of spatial variations of scattering and absorption coefficients of the medium.
Abstract: A method and processing device are presented for reconstructing an absorption and/or scattering image of a region of interest inside a scattering medium. A mathematical model is provided being representative of a relation between the distribution of the intensity and phase of electromagnetic radiation components scattered from a medium and a certain attenuation factor, which is function of spatial variations of scattering and absorption coefficients of the medium. The mathematical is used for processing a map of distribution of the intensity of electromagnetic radiation components scattered from known locations within the region of interest, thereby producing a halftone pattern of the region of interest.

34 citations

Journal ArticleDOI
TL;DR: By varying the absorption coefficient and width of an intralipid-India ink solution in a quasi-one-dimensional experiment, it is demonstrated that the transition location depends on the scattering coefficient as well as on the measuring solid angle.
Abstract: By varying the absorption coefficient and width of an intralipid–India ink solution in a quasi-one-dimensional experiment, we investigate the transition between the ballistic and the diffusive regimes. The medium’s attenuation coefficient changes abruptly between two different values within a single mean free path. This problem is analyzed both experimentally and theoretically, and it is demonstrated that the transition location depends on the scattering coefficient as well as on the measuring solid angle.

28 citations

Journal ArticleDOI
01 Nov 2005-EPL
TL;DR: In this article, the propagation of an arbitrary initially bounded wave function is investigated and the general solution for any such function is formulated, and the exact solution can be written as an expression that depends only on the values of the function and its derivatives at the boundaries.
Abstract: A general solution to the shutter problem is presented. The propagation of an arbitrary initially bounded wave function is investigated, and the general solution for any such function is formulated. It is shown that the exact solution can be written as an expression that depends only on the values of the function (and its derivatives) at the boundaries. In particular, it is shown that at short times (t << 2mx2/, where x is the distance to the boundaries) the wave function propagation depends only on the wave function's values (or its derivatives) at the boundaries of the region. Finally, we generalize these findings to a non-singular wave function (i.e., for wave packets with finite-width boundaries) and suggest an experimental verification.

27 citations

Journal ArticleDOI
TL;DR: The most essential result is a fundamental limitation on the width of the subwavelength soliton: the ratio of the FWHM of the bright soliton to the wavelength cannot be smaller than 1/2, and the same ratio for the dark soliton cannot be bigger than1/4.
Abstract: We analyze the effects of additional terms in the nonlinear Schrodinger equation for spatial solitons, directly derived from the Maxwell’s equations with the Kerr nonlinearity, on the shapes of bright and dark solitons with a fixed polarization. Combining analytical and numerical methods, we find that the additional terms always render the solitons broader. The most essential result is a fundamental limitation on the width of the subwavelength soliton: The ratio of the FWHM of the bright soliton to the wavelength cannot be smaller than 1/2, and the same ratio for the FWHM of the dark soliton cannot be smaller than 1/4.

25 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the authors review recent progress in inducing and harnessing stimulated Brillouin scattering (SBS) in integrated photonic circuits, with special attention paid to photonic integration of applications such as narrow-linewidth lasers, slow-and fast-light, microwave signal processing, and non-reciprocal devices.
Abstract: We review recent progress in inducing and harnessing stimulated Brillouin scattering (SBS) in integrated photonic circuits. Exciting SBS in a chip-scale device is challenging due to the stringent requirements on materials and device geometry. We discuss these requirements, which include material parameters, such as optical refractive index and acoustic velocity, and device properties, such as acousto-optic confinement. Recent work on SBS in nano-photonic waveguides and micro-resonators is presented, with special attention paid to photonic integration of applications such as narrow-linewidth lasers, slow- and fast-light, microwave signal processing, Brillouin dynamic gratings, and nonreciprocal devices.

291 citations

Journal ArticleDOI
TL;DR: Two types of ultrasound-mediated biophotonic imaging are reviewed–acousto-optical tomography and photo-acoustic tomography–both of which are based on non-ionizing optical and ultrasonic waves.
Abstract: This article reviews two types of ultrasound-mediated biophotonic imaging–acousto-optical tomography (AOT, also called ultrasound-modulated optical tomography) and photo-acoustic tomography (PAT, also called opto-acoustic or thermo-acoustic tomography)–both of which are based on non-ionizing optical and ultrasonic waves. The goal of these technologies is to combine the contrast advantage of the optical properties and the resolution advantage of ultrasound. In these two technologies, the imaging contrast is based primarily on the optical properties of biological tissues, and the imaging resolution is based primarily on the ultrasonic waves that either are provided externally or produced internally, within the biological tissues. In fact, ultrasonic mediation overcomes both the resolution disadvantage of pure optical imaging in thick tissues and the contrast and speckle disadvantages of pure ultrasonic imaging. In our discussion of AOT, the relationship between modulation depth and acoustic amplitude is clarified. Potential clinical applications of ultrasound-mediated biophotonic imaging include early cancer detection, functional imaging, and molecular imaging.

249 citations

Proceedings Article
04 May 2008
TL;DR: It is shown that new types of nonlinear self-trapped modes can exist in optical PT synthetic lattices.
Abstract: We investigate the effect of nonlinearity in novel parity-time (PT) symmetric potentials. We show that new types of nonlinear self-trapped modes can exist in optical PT synthetic lattices.

203 citations

Journal ArticleDOI
Jean Toulouse1
TL;DR: In this paper, a review of optical nonlinearities in optical fibers is presented, pointing out the essential material and fiber parameters that determine them, emphasizing their variations for different values of essential parameters.
Abstract: Optical nonlinearities give rise to many ubiquitous effects in optical fibers. These effects are interesting in themselves and can be detrimental in optical communications, but they also have many useful applications, especially for the implementation of all-optical functionalities in optical networks. In the present paper, we briefly review the different kinds of optical nonlinearities encountered in fibers, pointing out the essential material and fiber parameters that determine them. We describe the effects produced by each kind of nonlinearity, emphasizing their variations for different values of essential parameters. Throughout the paper, we refer to recent systems applications in which these effects have been dealt with or exploited.

148 citations