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Single Longitudinal Mode Blue-Violet Laser Diode for Data Storage
Single Longitudinal Mode Blue-Violet Laser Diode for Data Storage

... It is well known that volume holographic gratings (VHGs) have a narrow angular and spectral response [2]. Because of this unique property, a reflection-mode VHG will Bragg-match and strongly diffract only a narrow range of wavelengths anti-parallel to the incident beam. This property makes it possib ...
IOSR Journal of Applied Physics (IOSR-JAP)
IOSR Journal of Applied Physics (IOSR-JAP)

... Figure 3.2 shows that optical density decreases with increase in thickness, the higher steps of the wedge are dense, thus absorb more radiation than they transmit. The lower steps on the other hand are not as thick and hence readily transmit radiation, absorbing none at all. This implies that attenu ...
5377 17paper
5377 17paper

Investigation of nanoscale structural alterations of cell nucleus as an
Investigation of nanoscale structural alterations of cell nucleus as an

... can be achieved by super-resolution fluorescence microscopy techniques, such as stochastic optical reconstruction microscopy (STORM) [12], photoactivatable localization microscopy (PALM) [13], stimulated emission depletion microscopy (STED) [14] and 3D structured illumination microscopy (3D-SIM) [15 ...
characterization of nondiffracting bessel beams in the propagation
characterization of nondiffracting bessel beams in the propagation

... [7] and free-space optical communications [8]. For these applications, the useful part of the Bessel beams is often limited to their near field. As a matter of fact, the central lobe persists as long as there are off-axis lobes to replenish its diffraction losses and prevent it from spreading [9, 10 ...
Paper
Paper

... respectively. Recently, Bose-Einstein condensates illuminated by an off-resonant laser beam (“dressed condensates”) were used to realize phase-coherent amplification of matter waves [1,2]. The amplification process involved the scattering of a condensate atom and a laser photon into an atom in a rec ...
Ultrahigh Precision Absolute and Relative Rotation Sensing using
Ultrahigh Precision Absolute and Relative Rotation Sensing using

... many orders of magnitude by using a characteristic anomalous dispersion that corresponds to superluminal light propagation in the medium. Dispersion bounds for sensitivity enhancement are quantified by defining the critical anomalous dispersion (CAD) condition that can be experimentally realized usi ...
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Shifting the spherical focus of a 4Pi focusing system

... special principal surface (see Fig. 1 in [13]), which can eliminate the first-order axial aberration. Furthermore, for a Herschel-type focusing system the apodizer factor due to the conservation of energy appearing in the Richards–Wolf integral (1) and (2) is simply X(θ) = 1, for which a fundamenta ...
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Single-shot Detection of Wavepacket Evolution
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... sections. Therefore, the motion of the wavepacket can be monitored experimentally using the probe pulse to (de)excite the wavepacket to some final state. Depending on the specifics of the experiment, different types of information on the electron dynamics can be obtained by measuring the electronic pop ...
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Laser Beam Profile, Spot size and Beam Divergence

... The laser that we are working with is a rectangular one. So, any measurement done should has two primary orientation taken into consideration and the results should be given for both the orientations separately. The setup is very simple. We have a laser and a detector(for measuring the intensity) se ...
Bandgap-assisted surface-plasmon sensing Arnaud J. Benahmed* and Chih-Ming Ho
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... is intimately related to the contrast between the optical index of the medium n3 and the dielectric that forms the grating nd [13]. The reflectivity maps corresponding to structure (c) present two distinctive features. First, the average reflectivity, even outside the SPR, is lower than what is obta ...
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... © 2011 Bentham Science Publishers Ltd. ...
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Moiré and Fringe Projection Techniques

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1 Introduction - Stony Brook Laser Teaching Center
1 Introduction - Stony Brook Laser Teaching Center

... such as microfluidic systems, where precisely controlled circulating particles can mix and pump small amounts of liquid, or micromachines, where rotating particles can be used as actuators or generators of kinetic energy [4]. The purpose of the current research was to create an optical vortex beam s ...
wavelength dependence of the light-induced index
wavelength dependence of the light-induced index

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Reflectivity of Nonlinear Apodized Chirped Fiber Bragg Grating Under Water

... of the reflectivity with the wavelength of the signal traveling in the chirped FBG in the linear and nonlinear cases for the Sine profile. The variations of the reflectivity have been calculated under the effect of the temperature range 10 - 25 o C. The increase that occurs in the values of the refl ...
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Fused Silica Transmission Gratings

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... the focal plane, allowing the optical polarization Möbius strips hidden in this complex field structure to be observed (27). For this technique, we used a spherical gold nanoparticle on a glass substrate and scanned it through the field under study (Fig. 1A). The scattered and transmitted light was ...
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Deriving object visibilities from interferograms obtained with a fiber

... With a delay line, the observer has the capacity to control the overall optical pathlength difference (OPD) from the source to the recombination point. During data acquisition, the OPD is scanned around the zero pathlength difference. The nominal scanning speed v is the algebraic sum of the internal ...
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... The next confirmation. Veselago used plotting the course of rays to predict that flat plate from a material with negative refractive index n  1 has to function as a lens with the unique properties. Most of us are acquainted with the lenses from the materials with positive refraction in cameras, ma ...
The Balmer Lines of Hydrogen and Deuterium
The Balmer Lines of Hydrogen and Deuterium

... amplifier, carefully adjust the position of the Hg lamp until the signal is maximized. Lower the gain settings if necessary so that the output signal is not saturated. Now look for the line in 2nd order. Double the line vacuum wavelength and then apply the difference between your observed line posit ...
Displacement Measuring Interferometry
Displacement Measuring Interferometry

...  −2πi nz2  E2 (t , z2 ) = r2E0 exp(2πift)exp  ...
Fast-Fourier-domain delay line for in vivo optical coherence
Fast-Fourier-domain delay line for in vivo optical coherence

... the maximum group delay, the linearity of group delay to minimize distortion of the images, the cost and availability of components, the flatness of the optical response 共in amplitude and phase兲 over the bandwidth of the light source, the repetition rate necessary for the desired image acquisition t ...
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Phase-contrast X-ray imaging



Phase-contrast X-ray imaging (PCI) or phase-sensitive X-ray imaging is a general term for different technical methods that use information concerning changes in the phase of an X-ray beam that passes through an object in order to create its images. Standard X-ray imaging techniques like radiography or computed tomography (CT) rely on a decrease of the X-ray beam's intensity (attenuation) when traversing the sample, which can be measured directly with the assistance of an X-ray detector. In PCI however, the beam's phase shift caused by the sample is not measured directly, but is transformed into variations in intensity, which then can be recorded by the detector.In addition to producing projection images, PCI, like conventional transmission, can be combined with tomographic techniques to obtain the 3D distribution of the real part of the refractive index of the sample. When applied to samples that consist of atoms with low atomic number Z, PCI is more sensitive to density variations in the sample than conventional transmission-based X-ray imaging. This leads to images with improved soft tissue contrast.In the last several years, a variety of phase-contrast X-ray imaging techniques have been developed, all of which are based on the observation of interference patterns between diffracted and undiffracted waves. The most common techniques are crystal interferometry, propagation-based imaging, analyzer-based imaging, edge-illumination and grating-based imaging (see below).
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