Photorefractive (PR) holograms can be fixed with various degrees of success.1-4 These usually involve the replacement of the original electronic charge by a relatively immobile ionic charge. When such holograms are reconstructed, by illuminating with the readout wave, a new dynamic electronic hologram is generated by the spatial interference of the readout and the diffracted waves. The superpos...

Spectral-beam-combining (SBC) systems utilizing multiple volume Bragg gratings must be carefully analyzed to maximize channel density and efficiency, and thus output radiance. This analysis grows increasingly difficult as the number of channels in the system increases, and heuristic optimization techniques are useful tools for exploring the limits of these systems. We explore three classes of m...

Inverse wave scattering problems arise in many applications including computerized/diffraction tomography, seismology, diffraction/holographic grating design, object identification from radar singals, and semiconductor quality control. Efficient algorithms exist for some inverse wave scattering problems in the low-and high-frequency regime or with weak scatterers. However, inverse wave scatteri...

One of the challenges for azobenzene-based materials in fabricating rewritable surface relief gratings is long response time procedure holographic recording, making it inefficient real-time applications. In this study, a small molecule azobenzene compound with facile fabrication route presented. By total recording intensity 200 mW/cm2, grating modulation depth 758 nm can be formed 5 min. The ±1...

In this study, a new approach for simulation of electric field enhancement ofplane wave laser around optical antenna was used to convert free-propagating opticalradiation to localized energy. A tapered gold tip design as a novel geometry of opticalantenna is introduced and numerically analyzed based on particle swarm optimization(PSO) by solving the Maxwell equations wit...

Grazing-angle scattering (GAS) is a type of Bragg scattering of waves in slanted non-uniform periodic gratings, when the diffracted order satisfying the Bragg condition propagates at a grazing angle with respect to the boundaries of a slablike grating. Rigorous analysis of GAS of bulk TE electromagnetic waves is undertaken in holographic gratings by means of the enhanced T-matrix algorithm. A c...

Extremely asymmetrical scattering (EAS) is an unusual type of Bragg scattering in slanted periodic gratings with the scattered wave (the +1 diffracted order) propagating parallel to the grating boundaries. Here, a unique and strong sensitivity of EAS to small stepwise variations of mean structural parameters at the grating boundaries is predicted theoretically (by means of approximate and rigor...

This paper demonstrates a label-free biological sensing method usmg nanoporous polymer gratings. The high index modulation (0.07) of the nanoporous polymer grating structure generates a high signal-to-noise ratio, making the structure an ideal label-free biodetection platform. The fabrication process of the nanoporous polymeric grating involves holographic interference patterning and a function...