Publications by authors named "G Vawter"

Optoelectronic devices are increasingly important in communication and information technology. To achieve the necessary manipulation of light (which carries information in optoelectronic devices), considerable efforts are directed at the development of photonic crystals--periodic dielectric materials that have so-called photonic bandgaps, which prohibit the propagation of photons having energies within the bandgap region. Straightforward application of the bandgap concept is generally thought to require three-dimensional (3D) photonic crystals; their two-dimensional (2D) counterparts confine light in the crystal plane, but not in the perpendicular z direction, which inevitably leads to diffraction losses.

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We present the results of subwavelength antireflection surfaces etched into GaAs for use at 975 nm. These surfaces comprise linear gratings with periods less than the wavelength of light in GaAs. The structure appears as a homogeneous birefringent film.

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We have fabricated subwavelength diffractive optical elements with binary phase profiles for operation at 975 nm. The individual surface-relief features of the elements are smaller than the wavelength of light in the material. By modulating the size and spacing of the features we form artificial, gradient, effective index-of-refraction surfaces.

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An analysis of digital and palmar dermatoglyphic patterns was conducted in 173 victims of the sudden infant death syndrome (SIDS). The results expose four dermatoglyphic regions with pattern frequencies differing from those in a control population. These are an excess of Sydney creases, hypothenar patterns, open fields (with fewer vestiges) in interdigital region IV, and arches on all digits (females only).

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