In this work, the monitoring of the etching process up to a diameter of 30 μm of two LPFG structures has been compared, one of them had initially 125 μm, whereas the second one had 80 μm. By tracking the wavelength shift of the resonance bands during the etching process it is possible to check the quality of etching process (the 80 μm fibre performs better than de 125 μm fibre), and to stop for...

Nanoscale features as small as 65 +/- 5 nm have been formed reproducibly by using 520 nm femtosecond pulsed excitation of a 4,4'-bis(di-n-butylamino)biphenyl chromophore to initiate crosslinking in a triacrylate blend. Dosimetry studies of the photoinduced polymerization were performed on chromophores with sizable two-photon absorption cross-sections at 520 and 730 nm. These studies show that s...

Phase measurements on self-assembled three-dimensional photonic crystals show that the group velocity of light can flip from small positive (slow) to negative (superluminal) values in samples of a few mum size. This phenomenon takes place in a narrow spectral range around the second-order stop band and follows from coupling to weakly dispersive photonic bands associated with multiple Bragg diff...

This study exhibited the correlated color temperature (CCT)- and color-rendering index (CRI)-tuning behavior of light emission from white light-emitting diodes (WLEDs) using three-dimensional non-close-packed (3D NCP) colloidal photonic crystals (CPhCs). The CCT of approximately 5300 K (characteristic of cold WLEDs) of white light propagated through the NCP CPhCs dropped to 3000 K (characterist...

This paper deals with single layer polarization independent Frequency selective surface (FSS) which acts as a triple band reject filter. The two stop bands are broad with percentage bandwidth 11.16% and 10.13% and one is narrow with 3.33% bandwidth. The band ratio is more than 1.5 and band separation is around 30-35dB. This design is investigated theoretically by ANSOFT® Designer software and p...

Polymeric molds of the layer-by-layer photonic crystal can be economically synthesized with a microtransfer molding technique. The refractive indices of these molds are low, preventing formation of a photonic bandgap. We find that such molds can be conformally coated with higher-index material. Photonic band calculations find structures in which conformally coated layer-by-layer molds have comp...

Experimental measurements of acoustic transmission through a solid-solid two-dimensional binary-composite medium constituted of a triangular array of parallel circular steel cylinders in an epoxy matrix are reported. Attention is restricted to propagation of elastic waves perpendicular to the cylinders. Measured transmitted spectra demonstrate the existence of absolute stop bands, i.e., band ga...

Linear chains of metallic nanoparticles that are sequentially rotated about the chain axis display interesting polarization-sensitive optical properties. Such twisted chains posses and extend properties of chiral gratings and general periodic gratings. They are characterized by high anisotropy and polarization sensitivity, and have subwavelength transverse dimensions. These structures are shown...

In this paper, we consider a class of FIR filters defined by the first order difference routing digital filter (DRDF) structure and sums of two powers–of–two coefficients. A novel design method is developed for constructing high quality filters with reference to the min–max error criterion. This method is highly efficient in terms of computational time. Simulation studies show a large improveme...

Broadband surface phonon wave packets on a phononic crystal made up of a microstructured line pattern are tracked in two dimensions and in real time with an ultrafast optical technique. The eigenmode distribution and the 2D acoustic band structure are obtained from spatiotemporal Fourier transforms of the data up to 1 GHz. We find stop bands at the zone boundaries for both leaky-longitudinal an...