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In this paper, the photonic band-gap (PBG) maps of fundamental photonic crystal (PhC) lattices are presented, and discussed. Two fundamental types of lattice: square and hexagonal (triangular, graphite or honeycomb and kagome) with circular, square, and hexagonal hole shapes are considered. Because they show the largest area gap map and because of the relative ease of fabrication of circular holes, it can be asserted that square and triangular lattices of circular holes offer the best choice of two dimensionally periodic photonic crystal (PhC) structure. Graphite and kagome lattices of circular holes in GaAs also show large area gap maps (and the largest gap map is for the second or third higher PBG region). So graphite and kagome lattices are also relevant for exploitation in PhC devices. At the scale required, fabrication process limitations are a significant problem for the realization of hole shapes other than circular. [ABSTRACT FROM AUTHOR]

Presents study which measured simultaneous depth profiles for hydrogen and lithium in proton-exchanged lithium niobate crystals. Experimental details; Results and discussion; Conclusion.

Polystyrene-based three-dimensionally periodic photonic crystals have been fabricated by the capillary growth method. By applying uniaxial pressure along the <111> direction of the face-centred cubic opal structure, it has been found that the photonic stopband can be shifted towards shorter wavelengths. This shift is found to be irreversible and occurs as the effective refractive index increases and the interplanar spacing decreases. Replica grating structures have also been created by applying pressure along the <111> direction. Structures replicated from one-dimensionally periodic triangular gratings with periodicities of 300 and 1200 mm-1 were imposed on the synthetic opal. [ABSTRACT FROM AUTHOR]

We demonstrate, in a planar two-dimensional (2D) configuration, in the optical regime a clear association of two photonic crystal elements and the ability to produce a low-loss coupled system. A channel waveguide is brought to between two and five crystal rows (450 to 1126 nm) from a 2D microcavity fabricated in a GaAs/AlGaAs waveguide. We probe these two elements individually and explore their interaction. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We have used transmission measurements to estimate the propagation loss of submicron channels defined in two-dimensional photonic crystals patterned into a Ga(Al)As waveguide. The measured propagation loss of the fundamental mode is indistinguishable from the material absorption, setting an upper limit of 50 cm-1 (2 dB per 100 μm). We also find that, provided the etching is deep enough, propagation losses of these photonic crystal waveguides are lower than those of ridge waveguides etched in the same run. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]