Related papers: A composite open resonator for compact X-ray sourc…
We investigate the finite source size effect in the context of the wave optics in the gravitational lensing. The magnification of an extended source is presented in an analytic manner for the singular isothermal sphere lens model as well as…
Quasi-stellar object (QSO) spectral templates are important both to QSO physics and for investigations that use QSOs as probes of intervening gas and dust. However, combinations of various QSO samples obtained at different times and with…
We report the first results from an X-ray polarimeter with a micropattern gas proportional counter using an amorphous silicon active matrix readout. With 100% polarized X-rays at 4.5 keV, we obtain a modulation factor of 0.33 +/- 0.03,…
The effective mass and decay width of the $\phi$ meson in the isospin asymmetric hot and dense resonance matter are studied using the effective Lagrangian framework considering the $\phi K \bar K $ interactions at one-loop level. In…
Fiber Fabry--Perot (FFP) resonators of a few centimeters are optimized as a function of the reflectivity of the mirrors and the dimensions of the intra-cavity waveguide. Loaded quality factor in excess of 10^9, with an optimum of…
We propose a new shape-based modeling technique for applications in imaging problems. Given a collection of shape priors (a shape dictionary), we define our problem as choosing the right dictionary elements and geometrically composing them…
The concept of nonradiative dielectric resonator is generalized in order to include axially open configurations having rotational invariance. The resulting additional nonradiative conditions are established for the different resonance modes…
Improving angular resolution is one of X-ray astronomy's big challenges. While X-ray interferometry should eventually vastly improve broad-band angular resolution, in the near-term, X-ray telescopes will sacrifice angular resolution for…
The effect of gravity and proper acceleration on the frequency spectrum of an optical resonator - both rigid or deformable - is considered in the framework of general relativity. The optical resonator is modeled either as a rod of matter…
Excited hadrons are seen as resonances in the scattering of lighter stable hadrons like $\pi$, $K$ and $\eta$. Many decay into multiple final states necessitating coupled-channel analyses. Recently it has become possible to obtain…
The K-alpha resonance complexes in oxygen ions O I - O VI are theoretically computed and resonance oscillator strengths and wavelengths are presented. The highly resolved photoionization cross sections, with relativistic fine structure, are…
In this study, we investigate a novel design of an on-chip nested coupled ring resonator to enhance the quality factor and the effective length of the resonator. The configuration consists of an open ring and racetrack resonator, with…
One of the major goals of research for laser-plasma accelerators is the realization of compact sources of femtosecond X-rays. In particular, using the modest electron energies obtained with existing laser systems, Compton scattering a…
Extensive programs of follow-up observations of hard X-ray selected sources have unambiguosly revealed that the sources of the X-ray background are characterized by an extremely large dispersion in their optical magnitude and spectroscopic…
We have built and tested a compact, low-cost, but very-high-performance astronomical polarimeter based on a continuously rotating half-wave plate and a high-speed imaging detector. The polarimeter is suitable for small telescopes up to ~1 m…
Bright sources of high-energy X-rays and electrons are indispensable tools in advanced imaging. Yet, current laser-driven systems typically support only single-modality imaging, require complex infrastructure, or operate at low repetition…
We present a novel design of loop-gap resonator, the loop-zag resonator, for sub-X-band electron-spin resonance spectroscopy. The loop-zag design can achieve improved coupling to small-sample spin systems through the improvement of sample…
Optical frequency combs have had a remarkable impact on precision spectroscopy. Enabling this technology in the x-ray domain is expected to result in wide-ranging applications, such as stringent tests of astrophysical models and quantum…
Prospects of parametric x-rays (PXR) application for the development of a tuneable quasi-monochromatic x-ray source for medical imaging are discussed. Analysis of basic requirements for electron accelerator shows that it must be relatively…
Optical microresonators are characterized by a comb of resonances that preserve similar characteristics over a broad spectral interval. However, for many applications it is beneficial to selectively control of the quality factor (Q) of one…