Photons in polychromatic rotating modes

We propose a quantum theory of rotating light beams and study some of its properties. Such beams are polychromatic and have either a slowly rotating polarization or a slowly rotating transverse mode pattern. We show there are, for both cases, three different natural types of modes that qualify as rotating, one of which is a new type not previously considered. We discuss differences between these three types of rotating modes on the one hand and non-rotating modes as viewed from a rotating frame of reference on the other. We present various examples illustrating the possible use of rotating photons, mostly for quantum information processing purposes. We introduce in this context a rotating version of the two-photon singlet state.Comment: enormously expanded: 12 pages, 3 figures; a new, more informative, but less elegant title, especially designed for Phys. Rev.

Self-assembly of amorphous calcium carbonate microlens arrays

Biological materials are often based on simple constituents and grown by the principle of self-assembly under ambient conditions. In particular, biomineralization approaches exploit efficient pathways of inorganic material synthesis. There is still a large gap between the complexity of natural systems and the practical utilization of bioinspired formation mechanisms. Here we describe a simple self-assembly route leading to a CaCO3 microlens array, somewhat reminiscent of the brittlestars' microlenses, with uniform size and focal length, by using a minimum number of components and equipment at ambient conditions. The formation mechanism of the amorphous CaCO3 microlens arrays was elucidated by confocal Raman spectroscopic imaging to be a two-step growth process mediated by the organic surfactant. CaCO3 microlens arrays are easy to fabricate, biocompatible and functional in amorphous or more stable crystalline forms. This shows that advanced optical materials can be generated by a simple mineral precipitation

Scanning force microscopy of coatings and nanostructured surfaces

The capability of scanning force microscopy and subsequent PSD data evaluation for the investigation of functional surface nanostructures is demonstrated. Critical effects emerging from measurements in the nanometer scale are discussed

Roughness structures of ultrahydrophobic and hydrophilic coatings on glass

With specific modelling, measurement, and analysis procedures it is possible to predict, define and control roughness structures for optimal hydrophobic and hydrophilic coatings on glass. Examples are given for sol-gel-layers with ultrahydrophobic and hydrophilic properties

Roughness evolution of multilayer coatings for 6.7 nm and its impact on light scattering

The roughness evolution as well as its impact on the light scattering properties of La/B4C and Ru/B4C multilayer coatings for a wavelength of 6.7 nm are studied by analyzing multilayer stacks with different numbers of layers

Creating Micro- and Nanostructures on Tubular and Spherical Surfaces

The authors developed a new technique to create micro- and nanometer scale structures on curved free-standing objects by combining embossing/imprinting lithography approaches with mechanical loadings on elastic films. Embossing/imprinting generates small structures and mechanical loading determines shape or geometry of the final object. As a result, a portion of the tubes with a radius between 0.5 and 3.5 mm and a portion of the spheres with a radius between 2.4 and 7.0 mm were fabricated with grating line features (period of 700 nm) and microlens array features (lens radius of 2.5 µm) atop, respectively. It was found that both static analyses and finite element models can give good estimates on the radii of those curved objects, based on the dimension of the two layers, loading format, as well as mechanic strains. Thus, good control over shape and dimension of the free-standing structure can be achieved

Instrument for the Measurement of EUV Reflectance and Scattering - MERLIN

A new system is presented for measurements of angle resolved scatter and reflectance at 13.5 nm in the extreme ultraviolet spectral range. The system enables the at-wavelength characterization of EUV optical components. Examples are presented for Mo/Si multilayers deposited onto super polished substrates

Surface roughness characterization of smooth optical films deposited by ion plating

The surface topography of Ta205 and Si02 layers deposited by ion plating was studied by atomic force microscopy (AFM) and total integrated light scattering. A nearly perfect replication of the microroughness of superpolished and conventionally polished substrates was observed by AFM. Consequently, the scattering was not increased by the intrinsic microroughness of the films. However, local scatter maxima occured that were attributed to local defects

IAD of oxide coatings at low temperature: a comparison of processes based on different ion sources

A comparative study of different ion and plasma assisted physical vapor deposition processes at low temperature is reported. To work out a clear comparison of the different processes, the object of the study are single layers of different metal oxides like Ta2O5, TiO2, SiO2 and mixed oxides like H4 (Merck) deposited on glass and silicon substrates. Three different types of ion- (or plasma-respectively) sources are used: the cold cathode ion source from Denton (CC 104), the end hall ion source Mark II from CSC and the advanced plasma source from Leybold. Each of these processes is run under conditions concerning process parameters like bias, ion current, ion energy, beam characteristics and gas flow, which were understood to be optimized also to maintain long-term stability as realistic production conditions. The resulting metal oxide single layers are characterized by their optical properties, dispersion curves for NUV and VIS as well as absorption and scatter at discrete wavelengths. Also discussed are mechanical properties like hardness and adherence. A test method is presented which clearly shows the superior behavior of the IAD coatings