Over the last 10 years, neutron reflectivity has emerged as a powerful technique for the investigation of surface and interfacial phenomena in many different fields. In this paper, a short review of some of the work on neutron reflectivity and grazing-angle diffraction as well as a description of the current and planned neutron rcflectometers at NIST is presented. Specific examples of the chara...

This paper presents the modeling and simulation of an optical fiber Bragg grating for maximum reflectivity, minimum side lobe. Gating length represents as one of the critical parameters in contributing to a high performance fiber Bragg grating. The reflection spectra and side lobes strength were analyzed with different lengths .The side lobes have been suppressed using raised cosine apodization...

An experimental arrangement is described for determination of refractive indices n and extinction coefficients k of strongly absorbing liquids and solids over a wide spectral region. The reflectivity of parallel polarized light vs angle of incidence is measured, and the optical constants are calculated from the minimum parallel reflectivity and the corresponding Brewster angle. The accuracy of ...

The so-called self consistency method uses the fact that the true radar co-polar reflectivity (Zh e) and the differential reflectivity (Zdr ) can be used to predict the specific differential propagation phase (Kdp) at each radar range gate. The application of this method at S-band is relatively straight-forward as has been demonstrated in the past (e.g. Goddard et al., 1994). At C-band, one nee...

We report the observation of a sharp band-edge response in spectrally resolved differential reflectivity experiments on GaMnAs, in contrast to linear optical experiments in which large band-tail effects are known to dominate. The differential reflectivity response exhibits a blue shift relative to results in GaAs and LT-GaAs, consistent with the valence-band model of ferromagnetism. Our results...

We propose using blazed gratings in the resonance domain with period larger than the wavelength for anti-reflection and polarization selection. The inherent problem in this region is wavelength dispersion, which is solved by analyzing the total reflectivity and electric field distribution. The positional relationship between the area of strong electric field, and the side and tip of the grating...

We report on a black metamaterial of gold fabricated on a lotus leaf that was used as a template. In spite of the extremely thin gold coating (10-nm thick) on the lotus leaf, the surface shows reflectivity below 0.01 over the entire visible spectral range. Finite-difference time-domain (FDTD) calculations suggest that the low reflectivity stems from the secondary structures on the lotus leaf, w...

In the Tropics more small drops and less large drops were found in oceanic precipitation than in continental precipitation at the given reflectivity. Similarly, more small drops and less large drops were found in remnants of a tropical cyclone than in frontal precipitation in mid-latitude site at the same reflectivity. The presence of small drops was higher in deep convective regime than in str...

We theoretically verify that the threshold of an intracavity optical parametric oscillator pumped by a passively Q-switched laser is entirely controlled by the bleach of the saturable absorber not by the signal output reflectivity. We use a series of different output couplers to optimize the output performance. With a signal output reflectivity of 15%, we experimentally achieve an efficient sub...

We discuss mode-locking of low-gain solid-state lasers using a semiconductor saturable Bragg reflector structure. This recently developed low-loss mode-locking device consists of a single quantum well which acts as a saturable absorber incorporated into a high-reflectivity Bragg mirror. Highly stable mode-locking in solid-state lasers results from an ultrafast transient reflectivity in the devi...