An angular spectrum algorithm is presented for fast, near-field diffraction tomographic imaging with diffuse photon density waves in highly scattering media. A general relation in K space is derived that connects the spatial variations of the optical properties of heterogeneities to the spatial spectra of the measured scattered diffuse photon density waves. The theory is verified experimentally...

Pulsar winds shocked in the ambient medium produce spectacular nebulae observable from the radio through γrays. The shape and the spectrum of a pulsar wind nebula (PWN) depend on the angular distribution, magnetization and energy spectrum of the wind streaming from the pulsar magnetosphere, as well as on the pulsar velocity and the properties of the ambient medium. The advent of Chandra, with i...

A new illumination system for mask aligner lithography is presented. The illumination system uses two subsequent microlens-based Köhler integrators. The second Köhler integrator is located in the Fourier plane of the first. The new illumination system uncouples the illumination light from the light source and provides excellent uniformity of the light irradiance and the angular spectrum. Spatia...

An angular measuring system is the most important component of high-precision test turntables; its function and precision determine the turntable's function and precision. The angular measuring system's error was considered as a stationary signal in the past. An autocorrelation function and spectrum characteristics of the angular measuring system error are analyzed using the cyclostationary sig...

We use an iterative generalized least squares map-making algorithm, in conjunction with Monte Carlo techniques, to obtain estimates of the angular power spectrum from cosmic microwave background (CMB) maps. This is achieved by characterizing and removing the instrumental noise contribution in multipole space. This technique produces unbiased estimates and can be applied to an arbitrary experime...

A tomographic imaging system based on wavelength-scanning digital interference holography is developed by applying the angular spectrum method. Compared to the well-known Fresnel diffraction formula, which is subject to a minimum distance requirement in reconstruction, the angular spectrum method can reconstruct the wave field at any distance from the hologram plane. The new system allows three...

We discuss the mass spectrum of highly-excited nucleon and ∆ * resonances. The spectrum exhibits parity doublets, pairs of resonances of identical total angular momentum J but of opposite parity. It has been proposed that the parity doublets evidence restoration of chiral symmetry at large baryon excitation energies. We compare this conjecture with the possibility that high-mass states are orga...

The advent of high signal-to-noise cosmic microwave background (CMB) anisotropy experiments now allow detailed studies on the statistics related to temperature fluctuations. The existence of acoustic oscillations in the anisotropy power spectrum is now established with the clear detection of the first, and to a lesser confidence the second and the third, peak. Beyond the acoustic peak structure...

We compute the angular power spectrum of temperature anisotropies on the microwave sky in the cosmic texture theory, with standard recombination assumed. The spectrum shows`Doppler' peaks analogous to those in scenarios based on primordial adiabatic uctuations such as`standard CDM', but at quite diierent angular scales. There appear to be excellent prospects for using this as a discriminant bet...

We consider the problem of estimating the time differences of arrival (TDOAs) of multiple sources from a two-channel reverberant audio signal. While several clustering-based or angular spectrum-based methods have been proposed in the literature, only relatively small-scale experimental evaluations restricted to either category of methods have been carried out so far. We design and conduct the f...