Micro- and nanostructures enable specific optical functionalities, which rely on diffractive effects or effective medium
features, depending on pattern dimension and wavelength. Performance predictions of optical systems which make use
of nanostructured materials require having an accurate description of these materials ready to hand within the optical
design. At the one hand, nanostructure characteristics which result from rigorous electromagnetic modeling can be used
for the optical design. At the other hand, manufactured nanostructures may deviate from their idealized geometry, which
will affect the performance of the optical system, wherein these artificial structures will be used. Thus, detailed optical
characterization of the micro- or nanostructure functionality is prerequisite for accurate optical design and performance
prediction. To this end, several characterization techniques can be applied depending on the scope of the optical design,
finally. We report on a general route to include all accessible and required optical information about the nanostructured
material within a corresponding model of the nanostructure as a specific optical component which can be used within a
ray-trace engine, finally. This is illustrated by a meta-material with asymmetric transmission properties in some more
detail.
Metallic inclusions in layered structures can have noticeable effects onto scattering and absorption due to the coupling of
the external electromagnetic field and local charge oscillations. These effects are strongly related to both the geometry of
the individual particle as well as to the array structure. Having in mind the efficiency improvement of silicon solar cells
due to plasmonic effects, we report on the modeling and the fabrication of periodic arrays of metallic nanoparticles on
planar substrates. Different characterization techniques as atomic force microscopy (AFM), scanning electron
microscope (SEM) and optical measurements are applied which provide particular information with respect to the
fabricated structures, each. Special emphasis is placed on the clarification of the dominant features of the optical
characterization by detailed numerical analysis. This allows identifying significant modes of the planar geometry which
is complemented by the nanostructures, whose interplay with the radiation field does establish changes of the absorption
in the silicon layer, finally. These findings may be helpful for optimization and clarification of specific details of
technology, later on.
The design and the fabrication of a multilevel blazed grating in resonance domain for first order high efficiency
applications are presented. The design shows that a 3 phase level grating is sufficient to achieve efficiency of 90% in the
minus first diffraction order. The standard technology for the fabrication of multilevel grating consists in multistep
electron beam lithography and reactive ion beam etching of the grating profile into the fused silica substrate. Typical
fabrication errors of this technology approach, e.g. misalignment, reduce the theoretical reachable efficiency of the
grating. Two new technological approaches were investigated to avoid these typical fabrication errors and to improve the
multi level fabrication process. The designed grating has been fabricated by three different technological solutions and
the geometrical characterization as well as the diffraction performance are presented and discussed.
We discuss AFM (Atomic Force Microscopy) characterization in terms of critical dimension and depth for large area
micro-optical elements. Results are shown and discussed in comparison with other techniques, such as SEM (Scanning
Electron Microscopy) for CD measurements and FIB (Focused Ion Beam)-SEM characterization for the structure profile.
The new GaN lasers represent a unique combination of compactness, reliability, energy efficiency, and short wavelength.
With respect to the previous state of the art in direct laser write lithography, based on gas lasers, this is resulting in a
breakthrough, and is opening the way to real desktop micropatterning. The field of diffractive optics can immediately benefit
by the availability of a new breed of pattern generators, based on such sources, mainly for fast turnaround device
development. This paper presents the technical advantages involved in the use of 405 nm GaN lasers for one-step multilevel
patterning. Beam modulation, exposure control and overall process strategy are discussed. In order to evaluate the
effectiveness of the new solution, a sample fabrication of beam shapers is also presented.
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