Optical Interference Holography Research Articles

Graded photonic crystals by optical interference holography

We report on the fabrication of graded photonic crystals in dye doped dichromate gelatin emulsions using an optical interference holographic technique. The gradedness is achieved by imposing a gradient form factor in the interference intensity resulting from the absorption of the dye in the dichromate gelatin. Wider and deeper photonic bandgaps are observed for the dyed samples as compared to the un-dyed samples. Our method could open up a new direction in fabricating graded photonic crystals which cannot be achieved easily using other techniques.

Optics design of a top-cut prism interferometer for holographic photonic quasicrystals

Optical interference holography has been proved to be a useful technique in fabricating periodic photonic crystals in which electromagnetic waves are forbidden in certain frequency band-gaps. Compared to periodic crystals, quasicrystals have higher point group symmetry and are more favorable in achieving complete band-gaps. In this report, a top-cut prism interferometer is designed and optimized for photonic quasicrystals. By changing the prism parameters and characteristics of different beams, different quasicrystalline structures can be obtained. At the same time, the diffraction patterns of the designed structures are also provided and reveal the ten-fold symmetry of the structures more clearly. Furthermore, the effect of the intensity threshold on the quasicrystalline structures is also investigated. This will provide guidance for the large-area and fast production of ten-fold quasicrystalline structures with high quality.

Optical characterization of woodpile structures in gelatin emulsions fabricated by optical interference holography

A 4+1-beam optical interference holography technique, with four linearly polarized side beams arranged symmetrically around a circularly polarized central beam, was used to fabricate woodpile structures in holographic gelatin emulsions. The gelatin samples, particularly in three dimensions, were more uniform than those recorded using polymeric photoresists because of the self-supporting property of the gelatin. The gelatin woodpile samples exhibited clear directional stop bands in the angular transmittance measurements. Furthermore, by exploiting the swelling property of the gelatin, we were able to tune these directional stop bands by the amount of swelling. We also modeled the angular dependence of the stop bands by the reflections of the parallel layers inside the woodpile samples and good agreement with the experimental results was obtained.

Woodpile and diamond structures by optical interference holography

We report the use of an optical interference holographic setup with a five-beam configuration, consisting of four side beams and one central beam from the same half space, to fabricate woodpile and diamond structures for the use as photonic bandgap materials in which electromagnetic waves are forbidden in the bandgap. By exploiting the advantage of the binarization of the interference pattern, using intensity cut-off, either linear or circular central beam can be used. More importantly, the beam configurations can be easily implemented experimentally as compared to other configurations in which the interfering beams are counter-propagating from both half spaces.

Erratum: “Icosahedral quasicrystals by optical interference holography” [Appl. Phys. Lett. 89, 251111 (2006)

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Icosahedral quasicrystals for visible wavelengths by optical interference holography

Quasicrystals, realized in metal alloys, are a class of lattices exhibiting symmetries that fall outside the usual classification for periodic crystals. They do not have translational symmetry and yet the lattice points are well ordered. Furthermore, they exhibit higher rotational symmetry than periodic crystals. Because of the higher symmetry (more spherical), they are more optimal than periodic crystals in achieving complete photonic bandgaps in a new class of materials called photonic crystals in which the propagation of light in certain frequency ranges is forbidden. The potential of quasicrystals has been demonstrated in two dimensions for the infrared range and, recently, in three-dimensional icosahedral quasicrystals fabricated using a stereo lithography method for the microwave range and direct laser writing for the IR range. Here, we report the fabrication and optical characterization of icosahedral quasicrystals using a holographic lithography method for the visible range. The icosahedral pattern, generated using a novel 7-beam optical interference holography, is recorded on photoresists and holographic plates. Electron micrographs of the photoresist samples show clearly the symmetry of the icosahedral quasicrystals in the submicron range, while the holographic plate samples exhibit bandgaps in the angular-dependent transmission spectra in the visible range. Calculations of the bandgaps due to reflection planes inside the icosahedral quasicrystal show good agreement with the experimental results.

Icosahedral quasicrystals by optical interference holography

Optical interference holography has been proven to be a useful technique in fabricating periodic photonic crystals in which electromagnetic waves are forbidden in certain frequency band gaps. Compared to periodic crystals, quasicrystals, having higher point group symmetry, are more favorable in achieving complete band gaps. In this letter, we propose two seven-beam optical interference configurations based on the reciprocal vector space representation to fabricate icosahedral quasicrystals. Interference simulations for the quasicrystals exhibit the full symmetry of an icosahedron. The result paves the way for the fabrication of photonic quasicrystals using holographic lithography.

Realization of woodpile structure using optical interference holography

We report the use of a (4+1)-beam optical interference holography technique to fabricate woodpile structures in photo-resists. The configuration consists of 4 linearly polarized side beams arranged symmetrically around a circularly polarized central beam with all the beams from the same half space, making it easily accessible experimentally. The fabricated woodpile structures are in good agreement with model simulations. Furthermore, woodpiles with the diamond symmetry are also obtained by exploiting the shrinkage of the photo-resists. Bandgaps in the visible range are also observed for the samples with and without the correct stacking of the woodpile structures.

MICROWAVE HOLOGRAPHY BY MEANS OF OPTICAL INTERFERENCE HOLOGRAPHY

A microwave hologram was made by mapping the pattern of the thermal expansion of a resistive surface illuminated by a microwave field. The distribution of the displacement of the surface was mapped making use of optical interference holography techniques. The microwave hologram thus recorded was then photographically reduced in size. This hologram was next illuminated by a laser beam to yield the optical reconstruction of the microwave image.