SearcharxivSearch

arXiv subjects

A. I. Bishop

Publications and source records attributed to A. I. Bishop.

3 recordsLinked to original sources

Simple wave-optical superpositions as prime number sieves

We encode the sequence of prime numbers into simple superpositions of identical waves, mimicking the archetypal prime number sieve of Eratosthenes. The primes are identified as zeros accompanied by phase singularities in a physically generated wave-field for integer valued momenta. Similarly, primes are encoded in the diffraction pattern from a simple single aperture and in the harmonics of a single vibrating resonator. Further, diffraction physics connections to number theory reveal how to encode all Gaussian primes, twin-primes, and how to construct wave fields with amplitudes equal to the divisor function at integer spatial frequencies. Remarkably, all of these basic diffraction phenomena reveal that the naturally irregular sequence of primes can arise from trivially ordered wave superpositions.

physics.optics

Re-sampling of inline holographic images for improved reconstruction resolution

Digital holographic microscopy based on Gabor in-line holography is a well-known method to reconstruct both the amplitude and phase of small objects. To reconstruct the image of an object from its hologram, obtained under illumination by monochromatic scalar waves, numerical calculations of Fresnel integrals are required. To improve spatial resolution in the resulting reconstruction, we re-sample the holographic data before application of the reconstruction algorithm. This procedure amounts to inverting an interpolated Fresnel diffraction image to recover the object. The advantage of this method is demonstrated on experimental data, for the case of visible-light Gabor holography of a resolution grid and a gnat wing.

physics.optics

Numerical Modelling of Optical Trapping

Optical trapping is a widely used technique, with many important applications in biology and metrology. Complete modelling of trapping requires calculation of optical forces, primarily a scattering problem, and non-optical forces. The T-matrix method is used to calculate forces acting on spheroidal and cylindrical particles.

physics.optics