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Sisay M THESIS - Addis Ababa University Institutional Repository
... refractive index data for the evaluation of concentration profiles. But the main limitation of the interferometric methods is their sensitivity to vibrations, and so they require precise optical conditions and limits their implementation in an industrial environment. Also, the acquired data has to b ...
... refractive index data for the evaluation of concentration profiles. But the main limitation of the interferometric methods is their sensitivity to vibrations, and so they require precise optical conditions and limits their implementation in an industrial environment. Also, the acquired data has to b ...
Beam shaping based on intermediate zone diffraction of a micro
... 3. Performance of a micro-slit/hole lens for beam forming We further evaluated the beam focusing of the 0th-order maxima for wider slits of interest (up to ten wavelengths). It was found, as shown in Fig. 5, that the focal length (distance of maxima to slit screen) can extend to a range of tens of w ...
... 3. Performance of a micro-slit/hole lens for beam forming We further evaluated the beam focusing of the 0th-order maxima for wider slits of interest (up to ten wavelengths). It was found, as shown in Fig. 5, that the focal length (distance of maxima to slit screen) can extend to a range of tens of w ...
Frequency domain optical parametric amplification - few
... amplification of subcycle pulses without increasing their duration. It can also be beneficial for future multicycle ultrahigh-energy systems where damage threshold of laser crystals and large compression gratings are an issue. Results The concept of FOPA. At the core of FOPA is the strategy of amplify ...
... amplification of subcycle pulses without increasing their duration. It can also be beneficial for future multicycle ultrahigh-energy systems where damage threshold of laser crystals and large compression gratings are an issue. Results The concept of FOPA. At the core of FOPA is the strategy of amplify ...
ComplexLightBookChapterEG
... The different sections also discuss and cite the various methods for producing these beams. The hope is that they will stimulate new research in imaging, manipulation, and new areas where complex light has yet to make an impact, leading to the discovery of new phenomena and applications. ...
... The different sections also discuss and cite the various methods for producing these beams. The hope is that they will stimulate new research in imaging, manipulation, and new areas where complex light has yet to make an impact, leading to the discovery of new phenomena and applications. ...
An overview of the terdiurnal tide observed by polar radars and optics
... An 2 hr component is generally smaller than the diurnal ,. hr and semidiurnal +, hr components, but has definitely been identified in various radar and optical observations. Earlier observations at Garchy (.1῍N) show small amplitude with intermittent occurrence like internal gravity waves and short ve ...
... An 2 hr component is generally smaller than the diurnal ,. hr and semidiurnal +, hr components, but has definitely been identified in various radar and optical observations. Earlier observations at Garchy (.1῍N) show small amplitude with intermittent occurrence like internal gravity waves and short ve ...
Detennining the Phase Diagra1n and Aggregate Size of a Chro1nonic Liquid Crystal J
... governed by the temperatures and pressures to which a material is subjected, and the majority of compounds change from solids to liquids to gases as the temperature increases under constant pressure. For one out of every several hundred randomly synthesized organic compounds, however, there exists a ...
... governed by the temperatures and pressures to which a material is subjected, and the majority of compounds change from solids to liquids to gases as the temperature increases under constant pressure. For one out of every several hundred randomly synthesized organic compounds, however, there exists a ...
Electron diffraction for analysing crystal orientation of thin films
... If the accelerating voltage of the electron is in the range of 20 - 200 V (sometimes up to 600 V) one speaks of low-energy electron diffraction (LEED). Electrons of this energy have a wavelength of about 1 Å(2.7 Å at 20 V and 0.5 Å at 600 V), i.e. comparable to the distance between atoms, and can ...
... If the accelerating voltage of the electron is in the range of 20 - 200 V (sometimes up to 600 V) one speaks of low-energy electron diffraction (LEED). Electrons of this energy have a wavelength of about 1 Å(2.7 Å at 20 V and 0.5 Å at 600 V), i.e. comparable to the distance between atoms, and can ...
T R ECHNICAL ESEARCH
... does not contain a DC term. The visibility of the output pattern (14) is higher than what can be obtained using a conventional Zernike filter, and is limited only by the noise level. The “price” paid for this visibility increase is that additional computations should be performed using two output im ...
... does not contain a DC term. The visibility of the output pattern (14) is higher than what can be obtained using a conventional Zernike filter, and is limited only by the noise level. The “price” paid for this visibility increase is that additional computations should be performed using two output im ...
10 fs ultrafast all-optical switching in polystyrene nonlinear photonic
... polystyrene material has a much larger Kerr nonlinear coefficient and much faster response speed than semiconductor materials. In conclusion, we have demonstrated an all-optical switching with ultrafast response time as short as 11 fs based on a three-dimensional polystyrene nonlinear photonic cryst ...
... polystyrene material has a much larger Kerr nonlinear coefficient and much faster response speed than semiconductor materials. In conclusion, we have demonstrated an all-optical switching with ultrafast response time as short as 11 fs based on a three-dimensional polystyrene nonlinear photonic cryst ...
Optimization of axial resolution in a confocal microscope with
... media by confocal systems with off-axis illumination and detection have been presented [12,13]. However, although these studies have demonstrated the power of off-axis geometry, this approach does not include diffraction effects that are the subject of this study. Unfortunately, other methods of tre ...
... media by confocal systems with off-axis illumination and detection have been presented [12,13]. However, although these studies have demonstrated the power of off-axis geometry, this approach does not include diffraction effects that are the subject of this study. Unfortunately, other methods of tre ...
OPTIMIZATION OF THE FIBER-OPITC FABRY-PEROT INTERFEROMETER CONSTRUCTION Małgorzata Jędrzejewska-Szczerska,
... frequency of the measurement signal gives information about the measurand (equation (8)), as shown in Fig.3. It can be noted that for ∆φ=0 there is no spectral modulation (Fig.3a)). If the phase difference between the interfering beams varies from zero, the function takes the form of the cosine curv ...
... frequency of the measurement signal gives information about the measurand (equation (8)), as shown in Fig.3. It can be noted that for ∆φ=0 there is no spectral modulation (Fig.3a)). If the phase difference between the interfering beams varies from zero, the function takes the form of the cosine curv ...
Nondiffracting Light Beams for Long Ranges
... This requirement occurs in many cases. Electromagnetic waves including light beams, however, spread by the diffraction effect. The beam divergence angle Δθ can be given by Δθ=λ/D (λ: wavelength, D : diameter of aperture). For getting a small divergence beam, the diameter of beam transmission must be ...
... This requirement occurs in many cases. Electromagnetic waves including light beams, however, spread by the diffraction effect. The beam divergence angle Δθ can be given by Δθ=λ/D (λ: wavelength, D : diameter of aperture). For getting a small divergence beam, the diameter of beam transmission must be ...
Nonlocal Labeling of Paths in a Single-Photon Interferometer
... where we have applied the condition that the beam splitters have r*r = t*t = 1 / 2. The detection probability will show oscillations 共i.e., fringes兲 as a function of ␦ with a visibility given by V = cos 21. When 1 = 0 one can understand the interference as arising due to the indistinguishability o ...
... where we have applied the condition that the beam splitters have r*r = t*t = 1 / 2. The detection probability will show oscillations 共i.e., fringes兲 as a function of ␦ with a visibility given by V = cos 21. When 1 = 0 one can understand the interference as arising due to the indistinguishability o ...
Transfer of Angular Momentum to Matter from Acoustical Vortices in
... the topological charge of the vortex, the disk radius, and its position along the main propagation axis. With the technique presented here, acoustical vortices become promising tools for controlling rotations of suspended objects in acoustic levitation devices without the need of a closed cavity. Ou ...
... the topological charge of the vortex, the disk radius, and its position along the main propagation axis. With the technique presented here, acoustical vortices become promising tools for controlling rotations of suspended objects in acoustic levitation devices without the need of a closed cavity. Ou ...
CHAPTER 1 PHYSICAL OPTICS: INTERFERENCE • Introduction
... varies sinusoidally with position, x. The parameter k = 2# $ is called the wavevector, where $ is the wavelength. The product kx is called the phase angle (= %). A negative (positive) sign indicates the wave is traveling to the right (left). Also, ! is the angular frequency of the wave given by ! = ...
... varies sinusoidally with position, x. The parameter k = 2# $ is called the wavevector, where $ is the wavelength. The product kx is called the phase angle (= %). A negative (positive) sign indicates the wave is traveling to the right (left). Also, ! is the angular frequency of the wave given by ! = ...
Overview of various methods for measuring a lens focal length
... This technique uses the Talbot effect: the image of a coherent wave with 2D periodic amplitude distribution, incident upon a diffraction grating, is regularly repeated. The distance between each self-image is the Talbot length ∆. If the wave interferes with another wave diffracted by a grating with ...
... This technique uses the Talbot effect: the image of a coherent wave with 2D periodic amplitude distribution, incident upon a diffraction grating, is regularly repeated. The distance between each self-image is the Talbot length ∆. If the wave interferes with another wave diffracted by a grating with ...
Prospects for atom interferometry
... atom experiments can be much more compact than in beam experiments. This is because atoms in a beam travel much faster and cover greater distances in the time of the interferometer, typically up to several metres, whereas cold atoms will only travel a few millimetres. Apart from the technical conven ...
... atom experiments can be much more compact than in beam experiments. This is because atoms in a beam travel much faster and cover greater distances in the time of the interferometer, typically up to several metres, whereas cold atoms will only travel a few millimetres. Apart from the technical conven ...
Total internal reflection holography for optical interconnections
... where i, r, 0, and R are the indices of the image, readout, object, and recording reference wave, respectively, and m is the diffraction order. For the following, we consider only the first diffraction order (m = 1). ...
... where i, r, 0, and R are the indices of the image, readout, object, and recording reference wave, respectively, and m is the diffraction order. For the following, we consider only the first diffraction order (m = 1). ...
863875
... and large area fabrication flexibility in a single step [20–25]. It has also been shown that optical field patterns belonging to all 14 Bravais crystallographic lattice 3D structures can be formed by designed plane wave interference [26, 27]. By means of a spatial light modulator (SLM-) assisted app ...
... and large area fabrication flexibility in a single step [20–25]. It has also been shown that optical field patterns belonging to all 14 Bravais crystallographic lattice 3D structures can be formed by designed plane wave interference [26, 27]. By means of a spatial light modulator (SLM-) assisted app ...
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... crystal input face. Such a periodic spatial modulation, as previously generated from multibeam interference 关9兴, provides ‘‘seeding noise’’ for observation of induced modulation instability. In addition to the incoherent beam, a broad and uniform ordinarily polarized coherent beam from the same lase ...
... crystal input face. Such a periodic spatial modulation, as previously generated from multibeam interference 关9兴, provides ‘‘seeding noise’’ for observation of induced modulation instability. In addition to the incoherent beam, a broad and uniform ordinarily polarized coherent beam from the same lase ...
Generation and Application of Bessel Beams in Electron Microscopy
... Beyond the examples mainly focused on vortex beams, relatively little work has been done with a view to shaping electron beams using holographic elements [5][8][9], and still less with reference to specific practical applications. This is not to suggest that this area is entirely unexplored; studies ...
... Beyond the examples mainly focused on vortex beams, relatively little work has been done with a view to shaping electron beams using holographic elements [5][8][9], and still less with reference to specific practical applications. This is not to suggest that this area is entirely unexplored; studies ...
Review !x
... ! We have coherent light incident from the left and a source of spherical wavelets at the center of each slit ! We see that the gray dashed lines represent lines along which there is constructive interference April 8, 2005 ...
... ! We have coherent light incident from the left and a source of spherical wavelets at the center of each slit ! We see that the gray dashed lines represent lines along which there is constructive interference April 8, 2005 ...
General principles of spectroscopy and spectroscopic analysis
... or more vibrations that may differ only by their orientation in space. These will have exactly the same energy and result in one absorption peak. In addition to the degeneracy of vibrational modes, there is also the requirement that a vibration result in a change in the dipole moment of the molecule ...
... or more vibrations that may differ only by their orientation in space. These will have exactly the same energy and result in one absorption peak. In addition to the degeneracy of vibrational modes, there is also the requirement that a vibration result in a change in the dipole moment of the molecule ...
Enhancement of absorption and color contrast in
... smaller than the spatial extent of our Ge thickness gradient, and therefore we assumed that the thickness change was negligible over the spot. We performed background subtraction and normalization to a flat silver mirror (reflectance 0.95). Given our 0.15 NA objective, the incoming and collected l ...
... smaller than the spatial extent of our Ge thickness gradient, and therefore we assumed that the thickness change was negligible over the spot. We performed background subtraction and normalization to a flat silver mirror (reflectance 0.95). Given our 0.15 NA objective, the incoming and collected l ...
Phase-contrast X-ray imaging
![](https://commons.wikimedia.org/wiki/Special:FilePath/Attenuation_and_phase_shift_of_electromagnetic_wave_propagating_in_medium_with_complex_index_of_refraction_n.png?width=300)
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).