Showing papers in "Optik in 2008"

TL;DR: A new method called fractional wavelet packet transform to encrypt images in this paper, in which fractional orders andWavelet packet filter are its two series of keys.

TL;DR: In this paper, the authors demonstrate the efficiency of holographic microscopy by showing 3-D views of the flow patterns around big spheres in various geometric arrangements, using latex microspheres and also red blood cells whose three-dimensional trajectories and velocities can be easily measured as a function of time with subsecond and micron resolution.

TL;DR: In this paper, the optical transfer functions of multiple ring resonator (MRR) filters were derived in signal flow graph diagrams and the theoretical results indicated that the optical loss in micro-rings has a strong influence on the characteristics of the MRR filters.

TL;DR: In this paper, the third-order nonlinear optical properties of Brilliant Crocein dye were measured by the Z-scan technique and measurements were carried out for different concentrations for different applications.

TL;DR: A fiber Bragg grating (FBG) sensor for the measurement of high temperature is proposed and experimentally demonstrated in this article, where the temperature is measured based on the wavelength shifts of the FBG induced by strain.

TL;DR: Using the two-wavelength methods of projection moire topography was investigated to measure the 3-D shape of an object with 2 π -ambiguity problems, proving that the proposed scheme is capable of finding absolute fringe orders and can be effectively overcome to treat large step discontinuities in measured objects.

TL;DR: In this paper, the effect of increase in signal input power for the three power compensation methods is compared in terms of eye diagram, bit error rate, eye closure penalty and output received power.

TL;DR: In this article, the infrared thermograph noncontact testing method is proposed for selecting sintering parameters and calculating thermophysical parameters reasonably, and the results indicate that the on-the-spot survey trend agrees with the simulation trend.

TL;DR: In this paper, the individual and combined effect of second-, third-, fourth-and fifth-order dispersion parameters on FWM at different input channel powers and core effective areas was analyzed.

TL;DR: Comparative studies of the different phase-shifting algorithms in DSPI for object deformation measurement are presented.

TL;DR: In this paper, the authors studied the superluminal behavior of a one-dimensional plasma photonic crystal (PPC) made of alternate thin layers of two materials namely plasma and dielectric materials.

TL;DR: In this paper, a simple theoretical investigation of the coupling efficiency between a laser diode and a single-mode fiber with a parabolic lens formed on the fiber tip is presented, and the results show that this technique is effective and will be of benefit to designing suitable microlenses applying the laser coupling technique.

TL;DR: In this article, a modified Fourier transform profilometry (FTP) based on a fringe pattern with two frequency components is proposed, which provides a larger measuring range than that of the traditional FTP.

TL;DR: This paper demonstrates a brand-new method for image enhancement by adjusting the contrast of different spatial frequencies that is easy to implement owing to its simple optical basis.

TL;DR: In this paper, the radiation force of highly focused Bessel-Gaussian beams (BGBs) on a dielectric sphere in the Rayleigh scattering regime is theoretically investigated.

TL;DR: In this paper, a simplified solar-blind UV atmospheric propagation model is introduced, and the NLOS UV communication system model is constituted based on the single scattering assumption, and numerical simulation is conducted for two typical geometry configurations and different modulation formats.

TL;DR: In this paper, the authors demonstrate the dynamic simulation of light traveling in a fiber ring resonator with a single coupler, and derive the transmission curves of the bistability and the instability as function of the insertion losses (γ) and the coupling coefficients (κ) of the coupler.

TL;DR: In this article, a linearly polarized plane wave hitting a boundary where one of such scalars, namely the Tellegen parameter (the non-reciprocity parameter of bi-isotropic materials) changes is examined.

TL;DR: In this article, the effects of the third-order dispersion increases with the third order dispersion coefficient and input power and result in pulse shift and energy decreases, and adding high-order nonlinear can partly overcomes these effects.

TL;DR: In this paper, the authors presented analytical expressions for first higher order modal field as well as cladding decay parameter in the case of graded index fiber using a series expansion method involving the Chebyshev technique.

TL;DR: Guiding of laser beam in plasma channel formed by short ionizing laser pulse is studied in this article, where a delayed pulse propagates through this channel diffraction, refraction and self-phase modulation results which are not balanced resulting in increase/decrease in beam width.

TL;DR: In this article, the authors considered the problem of the reflection and transmission of a plane wave due to a slab of an electro-optic structurally chiral material (SCM) and showed that the exhibition of the circular Bragg phenomenon by the SCM can be controlled not only by the sign and the magnitude of a dc electric field but also by its orientation in relation to the axis of helicoidal nonhomogeneity of the material.

TL;DR: In this article, the authors studied the focusing of a singular beam by a lens in the presence of spherical aberration and defocusing by using Fresnel-Kirchhoff diffraction integral for two different values of topological charge.

TL;DR: This work forms various important optical functions using a 4 x 4 homogeneous transformation matrix to design and analyze skew rays that cross flat optical boundary surfaces and addresses three important topics: the direction of a reflected or refracted ray is determined according to Snell's law, sensitivity analysis and aberration of polychromatic light.

TL;DR: A path-following phase unwrapping algorithm and a phase unwRApping algorithm based on discrete cosine transform (DCT) which accelerates the Computation and suppresses the propagation of noise are described.

TL;DR: In this article, it was shown that in the case of nonlinear holographic recording the two-wave approximation can be applied with the use of the effective value of the amplitudes of the refractive index modulation ( n 1, n 2, and n 3 ) for the materials having a nonlinear response to the holographic illumination.

TL;DR: In this paper, the authors present an overview of the communication modes in scalar diffraction theory and provide numerical examples of the modes and coupling strengths for a near-field geometry with a sub-wavelength size receiving domain.

TL;DR: In this paper, a novel high-speed image sensing technique with adjustable frame rate based on an ordinary CCD was proposed and the principle of the image sensor was analyzed, and the experimental results show that this sensor is fit to the measurements of sinusoidal phase modulating interferometer technique.

TL;DR: An undercover multiplexing technique to give additional protection for optical information encryption by using the aperture size of the pupil in the optical system, as it governs the speckle size, to produce a decorrelation between two consecutively stored Speckle patterns.

TL;DR: In this paper, a differential algebraic (DA) method has been developed for the aberration analysis of electron mirrors, where a single DA ray trace is performed on a non-standard extension of real number space called n D v, enabling the aberrations of a mirror system to be obtained, in principle up to arbitrary order n, and with very high accuracy.