Characterisation of width-dependent diffusion dynamics in rubidium-exchanged KTP waveguides.

Integrated χ devices are a widespread tool for the generation and manipulation of light fields, since they exhibit high efficiency, a small footprint and the ability to interface them with fibre networks. Surprisingly, some commonly used material substrates are not yet fully understood, in particular potassium titanyl phosphate (KTP). A thorough understanding of the fabrication process of waveguides in this material and analysis of their properties is crucial for the realization and the engineering of high efficiency devices for quantum applications.

Impact of carbon-ion implantation on the nonlinear optical susceptibility of LiNbO.

In this work we study the impact of ion implantation on the nonlinear optical properties in MgO:LiNbO via confocal second-harmonic microscopy. In detail, we spatially characterize the nonlinear susceptibility in carbon-ion implanted lithium niobate planar waveguides for different implantation energies and fluences, as well as the effect of annealing. In a further step, a computational simulation is used to calculate the implantation range of carbon-ions and the corresponding defect density distribution.

Vibrational properties of the LiNbO3 z-surfaces.

The existence of localized vibrational modes both at the positive and at the negative LiNbO3 (0001) surface is demonstrated by means of first-principles calculations and Raman spectroscopy measurements. First, the phonon modes of the crystal bulk and of the (0001) surface are calculated within the density functional theory. In a second step, the Raman spectra of LiNbO(3) bulk and of the two surfaces are measured.

Determination of molecular weight of heparin by size exclusion chromatography with universal calibration.

The molecular weight (MW) of heparin can be accurately determined by size exclusion chromatography using "universal calibration." A universal calibration curve was constructed for Superose 12 with standard pullulan samples and verified using characterized ficoll fractions. This calibration yielded the correct MW of heparin as determined by light scattering, when the ionic strength of the mobile phase was maintained over 1.

Polyelectrolyte complexes and layer-by-layer capsules from chitosan/chitosan sulfate.

Polyelectrolyte complex formation of chitosans of varying average molecular weight and degree of acetylation with chitosan sulfate or poly(styrene sulfonate) was studied by static light scattering in dilute solution at various ionic strengths. Unlike the molecular weight, the degree of acetylation was found to have a significant effect on the resultant structural densities of the complexes. The same system was applied to the preparation of micrometer-sized hollow shells by means of a layer-by-layer technique (in total eight layers).

Physicochemical studies on xylinan (acetan). I. Characterization by gel permeation chromatography on sepharose Cl-2B coupled with static light scattering and viscometry.

Laboratory-made samples of the polysaccharide xylinan (acetan) were fractionated on Sepharose Cl-2B using 0.1M NaCl as eluant. The weight average molar masses and intrinsic viscosities were estimated in the fractions by multiangle laser light scattering (off-line) and capillary viscometry, respectively.