This paper considers a range of plasmonic-black-metal polarizers suitable for ultra-short pulses. The polarizers consist of
a metal surface being nanostructured with a periodic array of ultra-sharp grooves with periods of 250-350 nanometers,
and groove depths around 500 nanometers. The surfaces can be designed such that practically all incident light with
electric field perpendicular to the groove direction is absorbed. The efficient absorption is due to incident light being
coupled into gap-plasmon polaritons that propagate downwards in the gaps between groove walls towards the groove
bottom, where it is then subsequently absorbed during propagation. Reflection is largely avoided due to an adiabatic
groove taper design. The other polarization, however, is very efficiently reflected, and the main point of this paper is that
the reflection is with negligible dispersive stretching even for ultra-short pulses of 5-10 femtoseconds temporal width in
the visible and near-infrared. Temporal pulse shapes after reflection are calculated by decomposing the incident laser
pulse into its Fourier components, multiplying with the reflection coefficient in the frequency domain, and then Fouriertransforming
the product back to the time-domain. Reflection of pulses is compared for polarizers based on different
metals (gold, nickel, chromium). Polarizers are studied for two groove-array designs and two directions of light
incidence, center wavelengths 650 nm and 800 nm, and pulse widths 5 fs and 10 fs for the incident pulse.
We present here an alternative approach to local nanoscale light sources for excitation of surface plasmons based on
second-harmonic generation (SHG) in inorganic crystalline nanowires. It is shown that the nanowires can serve as
tunable coherent local source for surface plasmon polariton (SPP) excitation. Inorganic crystalline nanowires made of
potassium niobate (KNbO3) have previously been shown to have a large second-order optical non-linearity, which allows
for efficient second-harmonic- and sum-frequency generation. It has also been demonstrated that the fields generated by
scattering off nanfibers deposited on an air/metal interface can couple to SPP modes at the interface and thereby excite
SPPs at the interface. We have combined SHG in nanowires with SPP excitation through scattering off nanowires
deposited on thin silver and gold surfaces. To detect second-harmonic radiation that has been efficiently coupled into
SPP modes at the air/metal interface, angular resolved leakage radiation spectroscopy was performed for pump
wavelengths between 800 and 1300 nm.
We have developed a photonic technology that allows for precise immobilisation of proteins to sensor
surfaces. The technology secures spatially controlled molecular immobilisation since the coupling of each
molecule to a support surface can be limited to the focal point of the UV laser beam, with dimensions as
small as a few micrometers. The ultimate size of the immobilized spots is dependent on the focal area of
the UV beam. The technology involves light induced formation of free, reactive thiol groups in molecules
containing aromatic residues nearby disulphide bridges. It is not only limited to immobilizing molecules
according to conventional patterns like microarrays, as any bitmap motif can virtually be used a template
for patterning. We now show that molecules (proteins) can be immobilized on a surface with any arbitrary
pattern according to diffraction patterns of light. The pattern of photo-immobilized proteins reproduces the
diffraction pattern of light expected with the optical setup. Immobilising biomolecules according to
diffraction patterns of light will allow achievement of smaller patterns with higher resolution. The
flexibility of this new technology leads to any patterns of photo-imprinted molecules, with micrometer
resolution, thus being of relevance for present and future applications in nanotechnologies.
We present a new photonic technology and demonstrate that it allows for precise immobilisation of biomolecules to
sensor surfaces. The technology secures spatially controlled molecular immobilisation since immobilisation of each
molecule to a support surface can be limited to the focal point of the ultraviolet (UV) beam, as small as a few
micrometers. We can immobilise molecules according to any pattern, from classical microarrays to diffraction patterns
creating unique watermarking safety patterns. Given that suitable protein markers exists for all relevant diseases it is
entirely feasible to test for a range of disease indicators (antigens and other markers) in a single test. Few micrometer
spotsize allows for a virtually unlimited number of protein spots in a multipotent microarray. This new technology
produces radically new photonics based microarray sensing technology and watermarking and has clear potential for
biomedical, bioelectronic, surface chemistry, security markers production, nanotechnology and therapeutical
applications. We also show an in depth analyses of the immobilized patterns and of the microarrays with our software
BNIP Pro.
Photonic induced immobilization of biosensor molecules is a novel technology that results in spatially oriented and
spatially localized covalent coupling of a large variety of biomolecules onto thiol reactive surfaces, e.g. thiolated glass,
quartz, gold or silicon. The reaction mechanism behind the reported new technology involves light-induced breakage of
disulphide bridges in proteins upon UV illumination of nearby aromatic amino acids resulting in the formation of reactive
molecules that will form covalent bonds with thiol reactive surfaces. This new technology has the potential of replacing
present micro dispensing arraying technologies, where the size of the individual sensor spots are limited by the size of the
dispensed droplets. Using light-induced immobilization the spatial resolution is defined by the area of the sensor surface
that is illuminated by UV light and not by the physical size of the dispensed droplets of sensor molecules. This new
technology allows for dense packing of different biomolecules on a surface, allowing the creation of multi-potent
functionalized materials, such as biosensors with micrometer sized individual sensor spots. Thus, we have developed the
necessary technology for preparing large protein arrays of enzymes and fragments of antibodies, with micrometer
resolution, without the need for liquid micro dispensing.
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