Investigations of two-photon polymerization of inorganic-organic hybrid materials initiated by femtosecond Ti:sapphire laser pulses are performed. First applications of this technique for the fabrication of three-dimensional microstructures and photonic crystals in inorganic-organic hybrid polymers with a structure size down to 200 nm and a periodicity of 450 nm are discussed.

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Sol‐gel synthesis allows inorganic–organic hybrid polymer materials (ORMOCER®s) to be produced, which can be functionalized to tailor their physical and chemical properties such as refractive index or optical loss. A particular material system is discussed here, which is synthesized without addition of water and is applied in optical communications. As examples for 2D and 2.5D technology, planar waveguides, stacked waveguides, and microlenses are shown. Using two‐photon polymerization initiated by femtosecond laser pulses, arbitrary 3D structures can be made in the submicrometer range. In particular, 3D photonic crystal structures are described and discussed.

The fabrication of sub-100 nm feature sizes in large-scale three-dimensional (3D) geometries by two-photon polymerization requires a precise control of the polymeric reactions as well as of the intensity distribution of the ultrashort laser pulses. The authors, therefore, investigate the complex interplay of photoresist, processing parameters, and focusing optics. New types of inorganic– organic hybrid polymers are synthesized and characterized with respect to achievable structure sizes and their degree of crosslinking. For maintaining diffraction-limited focal conditions within the 3D processing region, a special hybrid optics is developed, where spatial and chromatic aberrations are compensated by a diffractive optical element. Feature sizes below 100 nm are demonstrated.

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Oscillating ferromagnetic probes, as typically used in magnetic force microscopy (MFM), induce eddy currents within conducting materials. These currents lead to an electrodynamic interaction between the probe and sample. As a consequence, the oscillation of the probe is affected, leading to a contrast in the phase, amplitude, or frequency-shift image. Eddy current imaging is highly sensitive to local variations in the material composition, even involving the analysis of subsurface features. Furthermore, it is possible to image stray fields of ferromagnetic domains and walls with nonmagnetic but conducting probes being oscillated at close proximity to magnetic samples. The latter configuration induces eddy currents within the probe, leading to images with a resolution comparable with that of MFM. In order to understand the contrast, the induced eddy current density and the resulting force between probe and sample are calculated by solving the Helmholtz equation for a dipole oscillating above a conducting surface. Theory and experimental data confirm that eddy current microscopy (ECM) is a new powerful tool providing force microscopy with a certain material-sensitive contrast and additionally permitting an absolutely nondestructive imaging of the softest magnetic materials.The quality of materials in the near-surface region can be examined by using eddy current techniques, which are well known from nondestructive evaluation [1-3]. Inhomogenities such as precipitates or scratches, can significantly change the conductivity of materials and therefore also influence the local eddy current density. Usually, eddy currents are induced by suitable coils and are then detected inductively [2,3]. In most advanced setups, SQUIDs are employed [1,3]. The spatial resolution depends on the size of emitter and receiver and is low if compared with standard microscopy. The invention of scanning tunneling microscopy (STM) in 1982 [4] and the subsequent development of related methods have opened the possibility of analyzing a variety of physical quantities of a sample by applying one uniform principle: the detection of locally varying interaction by raster-scanning a sharp probe in close proximity across the sample surface. Probably the most important breakthrough arose from the possibility of measuring forces on a local scale with atomic force microscopy (AFM) [5]. This involves the investigation of insulating samples with high resolution. Both short-and long-range forces, are accessible. The latter category involves, as a particular kind of probe-sample interaction, magnetostatic forces. If these forces are utilized, magnetic domain configurations can be imaged with sub-100-nm resolution [6,7].In magnetic force microscopy (MFM), a ferromagnetic probe is scanned at some distance across the sample. The magnetostatic force acting on the probe or a related quantity is measured and plotted versus the probe position [7]. In conventional MFM, a dither piezo is used to oscillate the probe. The magnetostatic interaction leads to a change in o...

Sol-gel synthesis allows one to produce inorganic–organic hybrid polymer materials which can be functionalized in order to tailor their physical and chemical properties. Besides, the resulting material properties are significantly influenced by further technological processing of the materials in thin film technology, i.e., the photochemical and thermal curing of the materials. In order to investigate the relationship between technological processing and material properties, a model system containing methacrylic groups as organically polymerizable units is chosen. The degree of conversion of the C=C double bond of the methacrylic group in dependence of the ultraviolet (UV) initiator concentration upon processing is characterized using Fourier-transform infrared spectroscopy. The data are correlated to measurements of the refractive indices at selected wavelengths.