We analyze the formation of one-dimensional localized patterns in a nonlinear dissipative medium including a set of two narrow "hot spots" (HSs), which carry the linear gain, local potential, cubic self-interaction, and cubic loss, while the linear loss acts in the host medium. This system can be realized as a spatial-domain one in optics and also in Bose-Einstein condensates of quasiparticles ...

Monochromatic x-ray imaging has been shown to increase contrast and reduce dose relative to conventional broadband imaging. However, clinical sources with very narrow energy bandwidth tend to have limited intensity and field of view. In this study, focused fan beam monochromatic radiation was obtained using doubly curved monochromator crystals. While these optics have been in use for microanaly...

X-ray mirrors with high focusing performances are commonly used in different sectors of science, such as X-ray astronomy, medical imaging and synchrotron/free-electron laser beamlines. While deformations of the mirror profile may cause degradation of the focus sharpness, a deliberate deformation of the mirror can be made to endow the focus with a desired size and distribution, via piezo actuato...

Motion parallax has been shown to be an effective and unambiguous source of information about the structure of three-dimensional (3-D) surfaces, both when an observer makes lateral movements with respect to a stationary surface and when the surface translates with respect to a stationary observer (Rogers & Graham, 1979). When the same pattern of relative motions among parts of the simulated sur...

Many astronomical imaging studies, such as those of weak gravitational lensing, call for better angular resolution than is normally possible from the ground over wide fields of view . For many of these studies astronomers need images which show a consistent point spread function across the field even if this comes at the expense of the ultimate in angular resolution at the centre of the field. ...

Thermal noise in high-reflectivity mirrors is a major impediment for several types of high-precision interferometric experiments that aim to reach the standard quantum limit or to cool mechanical systems to their quantum ground state. This is for example the case of future gravitational wave observatories, whose sensitivity to gravitational wave signals is expected to be limited in the most sen...

Using a CO(2), cw, coherent lidar, we have measured the surface roughness of diffuse targets through 1000 m of turbulent atmosphere. The technique measures the phase fluctuations of the speckle field at the receiver and relates the measured phase variance to the surface roughness. Measurements were made with aluminum targets that had been sandblasted with 8-, 16-, and 30-grit material and also ...

We develop a general classification of the infinite number of families of solitons and soliton complexes in the one-dimensional Gross-Pitaevskii/nonlinear Schrödinger equation with a nonlinear lattice pseudopotential, i.e., periodically modulated coefficient in front of the cubic term, which takes both positive and negative local values. This model finds direct implementations in atomic Bose-Ei...

A numerical analysis of the system performance of the intracavity adaptive optics experiment is presented. The analysis begins with a detailed comparison of the calculated and experimentally measured sensitivities of the unstable laser to both intracavity phase-tilt and astigmatism aberrations. The appropriate sensitivity measures considered here will be the outcoupled power and the far-field b...

The electronic and structural properties of LiBO3 (B = V, Nb, Ta, Os) are investigated via first-principles methods. We show that LiBO3 belong to the recently proposed hyperferroelectrics (hyperFEs), i.e., they all have unstable longitudinal optic phonon modes. Especially, the ferroelectric-like instability in the metal LiOsO3, whose optical dielectric constant goes to infinity, is a limiting c...