Don M. Cottrell

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The Hilbert transform is useful for image processing because it can select which edges of an input image are enhanced and to what degree the edge enhancement occurs. However, the transform operation is one dimensional and is not applicable for arbitrarily shaped two-dimensional objects. We introduce a radially symmetric Hilbert transform that permits(More)
We report a new, to our knowledge, technique for encoding amplitude information onto a phase-only filter with a single liquid-crystal spatial light modulator. In our approach we spatially modulate the phase that is encoded onto the filter and, consequently, spatially modify the diffraction efficiency of the filter. Light that is not diffracted into the(More)
We show how to two dimensionally encode the polarization state of an incident light beam using a parallel-aligned liquid-crystal spatial light modulator (LCSLM). Each pixel of the LCSLM acts as a voltage-controlled wave plate and can be programmed over a 2pi phase range at a wavelength of 514.5 nm. Techniques are reviewed for either rotating the major axis(More)
Nondiffracting beams are of interest for optical metrology applications because the size and shape of the beams do not change as the beams propagate. We have created a generating pattern consisting of a linear combination of two nondiffracting patterns. This pattern forms a nondiffracting interference pattern that appears as a circular array of(More)
Nondiffracting beams are of interest for optical metrology applications because the size of the beam does not change as the beam propagates. However, accuracy can be increased if the diameter of the beam is smaller. One technique for accomplishing this is to use the dark axial intensity profile associated with a higher-order nondiffracting Bessel function(More)
We report a multiple imaging capability of replicated binary Fresnel phase-encoded lenses written on programmable spatial light modulators (SLMs). These lenses produce a large number (up to 9 x 9) of equally intense replica images from either an external object or from a pattern which is encoded onto the SLM along with the phase-encoded lens. Theoretical(More)
A space-variant optical correlator whose output depends on both the shape and the position of the input signal is introduced. This positionally sensitive correlator has potential applications in machine vision, cryptography, and optical logic. In this approach the input function undergoes a free-space Fresnel transform (which introduces the positional(More)
Nondiffracting beams are useful for alignment applications because the size of the beam does not change as the beam propagates. In this research we report a technique that allows for distance measurements with nondiffracting beams. With our approach a diffractive optical element is designed that generates two off-axis, tilted, nondiffracting Bessel function(More)
We report the use of two-dimensional, binary phase-only diffraction gratings written on a programmable magnetooptic spatial light modulator to interconnect optically an input laser beam to multiple output locations. We show that we can achieve programmable weighted interconnects between the source and two output locations as well as a fan-out capability to(More)