Showing papers by "Er'el Granot published in 2003"
TL;DR: A new method for viewing through turbid or obstructing media is proposed, which benefits from the advantages of the first-light technique: high resolution, simple algorithms, insensitivity to boundary condition, etc., without suffering from its main deficiencies.
Abstract: We propose a new method for viewing through turbid or obstructing media. The medium is illuminated with a modulated cw laser and the amplitude and phase of the transmitted (or reflected) signal is measured. This process takes place for a set of wavelengths in a certain wide band. In this way we acquire the Fourier transform of the temporal output. With this information we can reconstruct the temporal shape of the transmitted signal by computing the inverse transform. The proposed method benefits from the advantages of the first-light technique: high resolution, simple algorithms, insensitivity to boundary condition, etc., without suffering from its main deficiencies: complex and expensive equipment.
16 citations
TL;DR: It is shown both theoretically and experimentally that, unlike phase modulation, amplitude modulation increases the Brillouin amplifier gain and that this effect has a very narrow bandwidth.
Abstract: We investigate the spectral response of a Brillouin amplifier in the frequency regime within the stimulated-Brillouin-scattering (SBS) bandwidth. This is done by amplitude modulating the pump with a low frequency; therefore, unlike in previous studies, the spectrum of the modulated pump is, in all cases, smaller than the SBS bandwidth. We show both theoretically and experimentally that, unlike phase modulation, amplitude modulation increases the Brillouin amplifier gain and that this effect has a very narrow bandwidth. Only modulation frequencies that are lower than a certain cutoff frequency increase the gain. This cutoff frequency can be arbitrarily small.
14 citations
TL;DR: Gamma-ray-irradiated lead-silicate glass shows enhanced photo-induced quasi-phase-matched second-harmonic generation as mentioned in this paper, which is due to the formation of color centers, which serve as traps for space charge.
Abstract: Gamma-ray-irradiated lead-silicate glass shows enhanced photoinduced quasi-phase-matched second-harmonic generation This is due to the formation of color centers, which serve as traps for space charge, resulting in an internal dc field due to the coherent photovoltaic effect The color center formation also enhances the χ(3) nonlinearity, which contributes to the photoinduced quasi-phase-matched second-harmonic generation as well We separate these two contributions and show their respective roles
2 citations
TL;DR: In this article, the authors proved that for any point impurity, the conductance reduction in all the sub-bands is exactly 2e^2/h, and in the case of a surface defect, not only is the minimum independent of the defect characteristics, but the transmission matrix also converges to universal (defect-independent) values.
Abstract: Even a single point defect in a quantum wire causes a conductance reduction. In this paper we prove (without any approximations) that for any point impurity this conductance reduction in all the sub-bands is exactly 2e^2/h. Moreover, it is shown that in the case of a surface defect, not only is the conductance minimum independent of the defect characteristics, but the transmission matrix also converges to universal (defect-independent) values. We also discuss particle confinement between two arbitrarily weak point defects.
1 citations