Polarization maintaining single-mode low-loss hollow-core fibres.

Hollow-core fibre (HCF) is a powerful technology platform offering breakthrough performance improvements in sensing, communications, higher-power pulse delivery and other applications. Free from the usual constraints on what materials can guide light, it promises qualitatively new and ideal operating regimes: precision signals transmitted free of nonlinearities, sensors that guide light directly in the samples they are meant to probe and so on. However, these fibres have not been widely adopted, largely because uncontrolled coupling between transverse and polarization modes overshadows their benefits.

The role of thickness transitions in convective assembly.

Here we examine the microscopic details of convective assembly, a process in which thin colloidal crystals are deposited on a substrate from suspensions of nearly monodisperse spheres. Previously, such crystals have been shown to exhibit a strong tendency toward the face-centered cubic structure, which is difficult to explain on thermodynamic grounds. Using real-time microscopic visualization, electron microscopy, and scanning confocal microscopy, we obtain clues about the crystallization mechanism.

Colloidal crystal layers of hexagonal nanoplates by convective assembly.

Particles of the zeolite ZSM-2 prepared as nearly hexagonal nanoplatelets were coated onto flat substrates by a convective assembly technique. On the submillimeter scale, coatings ranged in patterns from striped to continuous. Particles were preferentially oriented out-of-plane, as supported by X-ray diffractometry.