Fresnel zone

About: Fresnel zone is a research topic. Over the lifetime, 2337 publications have been published within this topic receiving 37650 citations.

X-Ray Spectromicroscopy of 120-fs Laser-Produced Plasma

Abstract: X-ray spectra of various plasma microsources can be recorded simultaneously with spectral and spatial resolution using spectrograph with flat, convex or concave crystals and a slit placed parallel to the dispersion direction (see, for example, [1,2]). This approach is simple for realization, but the obtained spatial resolution is limited by the slit size. The slit size is usually not smaller than 20–30 μm, due to the dramatic reduction of the system throughput. High spatial resolution (below 10 μm) combined with relatively high throughput was obtained using a shadow technique [21]. A substantial improvement of spatial resolution (4–10 μm) has been achieved through the use of the crystals bent to a complex surfaces (such as, for example, sphere or tori or elliptically [3-10]). Further improvement of the spatial resolution toward achievement of the micron to the submicron level has been pursued using Fresnel structures such as transmission zone plates. However, the spectral resolution obtained by this approach is very limited.

Single-chip photonic banyan network realized by arrays of beam-steering VCSELs and reflective Fresnel zone plates

Abstract: Summary form only given. A single-chip photonic Banyan network has been demonstrated by using bean-steering VCSELs and reflective Fresnel zone plate array. The focusing mirror reduces the beam spot to 15 /spl mu/m, and can greatly increase the optical interconnection density.

The Infrared Polarization of Sea Radiance.

Abstract: : The Fresnel coefficients have been applied to the reflection of unpolarized monochromatic radiation by a sea water capillary wave facet. The result for a single tilted facet has been integrated over all possible tilts and wave numbers to predict the horizontal, vertical, and unpolarized infrared radiance arising from the wind-ruffled ocean surface.

New theory of optical scintillation for moderate to strong fluctuations

Abstract: A model of irradiance fluctuations for a propagating optic wave through a random medium is developed here under the assumption that small-scale irradiance fluctuations are modulated by large-scale irradiance fluctuations of the wave. The upper bound for small turbulent cells is defined by the smallest cell size the Fresnel Zone or transverse spatial coherence radius of the optical wave. The largest cell size between scintillation index, we also develop expressions for the irradiance covariance function and temporal spectrum of irradiance. Quantitative values predicted by these models agree well with experimental and simulation data previously published. An application of the method is also presented for uplink/downlink optical communication channels to/from a satellite.