Composite cavity for enhanced efficiency of up conversion.

Methods, apparatus and systems for an up-converter resonant cavity light emitting diode device includes a semiconductor light source, an up-converter to form the light emitter with up-converting materials and an electrical source coupled with the semiconductor light source for providing electrical energy to the semiconductor light source to provide a desired wavelength emitted light. The semiconductor light source is a resonant cavity light emitting diode or laser that emits an approximately 975 nm wavelength to provide electrical and optical confinement to the semiconductor light source to fonn a resonant cavity up-converting light emitting diode (UCIRCLED). Rows and columns of electrodes provide active matrix addressing of plural sets of UC/RCLEDs for display devices. The up-converter resonant cavity light emitting diode device has applications in head mounted projection display optical system using spectrally selective beam splitters to eliminate spectral overlap between colors a

Emissive Fibers Containing Up Converters Excited by GaAs Based Semiconductor Light Sources

Methods and systems for an emissive fiber capable of being used for making emissive fabric by providing an optical fiber having a core and and embedding up conversion particles into at least one of the cladding and core to produce an emissive fiber that emits visible light when excited by light from near infrared light source that excites the up conversion particles. The optical fiber can have a core index of refraction that is greater than or less than the refractive index of the cladding for near infrared light or an index difference between the core and cladding of zero. Plural optical fibers are intertwined to produce an emissive fabric, wherein coupling a light source with the emissive fibers transmits a light beam through the fiber to excite the up conversion particles to emit visible light. The up conversion material can be embedded into the core, the cladding, or both

Composite cavity for enhanced efficiency of up conversion.

Methods, apparatus and systems for an up-converter resonant cavity light emitting diode device includes a semiconductor light source, an up-converter to form the light emitter with up-converting materials and an electrical source coupled with the semiconductor light source for providing electrical energy to the semiconductor light source to provide a desired wavelength emitted light. The semiconductor light source is a resonant cavity light emitting diode or laser that emits an approximately 975 nm wavelength to provide electrical and optical confinement to the semiconductor light source to fonn a resonant cavity up-converting light emitting diode (UCIRCLED). Rows and columns of electrodes provide active matrix addressing of plural sets of UC/RCLEDs for display devices. The up-converter resonant cavity light emitting diode device has applications in head mounted projection display optical system using spectrally selective beam splitters to eliminate spectral overlap between colors a

Low voltage display or indicator systems employing combinations of up converters and semiconductor light sources.

Methods and systems for a combination of up converters and semiconductor light sources in low voltage display or indicator system that can be battery powered. The display or indicator system includes one or more spatial light modulators and one or more up converters in combination with one or more semiconductor light sources. The spatial light modulator can be a liquid crystal display or a micro electro mechanical system or other spatial light modulator and can use direct modulation of the semiconductor light sources to modulate the visible emission from the up converters. The spatial light modulator can be placed between the up converting light source and the viewer or behind the up converting light source depending on the type of spatial light modulator, or modulation may be applied directly to one or more semiconductor light sources or arrays of semiconductor light sources that excite the up converters

Combination of up-converting materials with semiconductor light sources

Methods, apparatus and systems for an up-converter resonant cavity light emitting diode device includes a semiconductor light source, an up-converter to form the light emitter with up-converting materials and an electrical source coupled with the semiconductor light source for providing electrical energy to the semiconductor light source to provide a desired wavelength emitted light. The semiconductor light source is a resonant cavity light emitting diode or laser that emits an approximately 975 nm wavelength to provide electrical and optical confinement to the semiconductor light source to form an up-converting resonant cavity light emitting diode (UCIRCLED). Rows and columns of electrodes provide active matrix addressing of plural sets of UCIRCLEDs for display devices. The up-converter resonant cavity light emitting diode device has applications in head mounted projection display optical system using spectrally selective beam splitters to eliminate spectral overlap between colors a

Neural correlates of the affect heuristic during brand choice

In this working paper it is investigated how affect and cognition interact in consumer decision making. The research framework is multidisciplinary by applying a neuroscientific method to answer the question which information is processed during brand choice immediately when the decision is computed in the test person’s brain. In a neuroscientific experiment test persons perform binary decision-making tasks between different brands of the same product class. The results suggest that the presence of the respondent’s first choice brand leads to a specific modulation of the neural brain activity, which can be described as neural correlate of Slovic’s affect heuristic concept.Neuroeconomics, brand choice, cognition, affect

Effectiveness and utility of acoustic recordings for surveying tropical birds

Although acoustic recordings have recently gained popularity as an alternative to point counts for surveying birds, little is known about the relative performance of the two methods for detecting tropical bird species across multiple vegetation types. During June and July 2008, we collected species detection/nondetection data to compare the performance of a quadraphonic acoustic recording system and point counts for estimating species richness and composition and detection probabilities of 15 rare, moderately common, and common tropical bird species across six structurally distinct vegetation types (coastal dune scrub, mangrove, low-stature deciduous thorn forest, early and late successional medium-stature semievergreen forest, and grazed pastures) in the northern Yucatan Peninsula.We selected five rare species endemic to the Yucatan Peninsula and 10 moderately common and common species that also occur in other tropical regions. Species richness and composition did not differ between survey methods in any of the vegetation types. At the population level, however, we found support for an effect of method on detection probability for most species. For 13 species, regardless of their abundance, acoustic recordings yielded detection probabilities as high as or higher than those for point counts across all vegetation types. The remaining two species were better detected by point counts in pastures and coastal scrub, where greater visibility likely improved sightings of these species. However, these species were detected as well as or better by acoustic recordings in forests and mangroves where detections were primarily auditory. In tropical regions where experienced field observersmay not be available and funding for field surveys may be limited, acoustic recordings offer a practical solution for determining species richness and composition and the occupancy patterns of most species. However, for some species, a combination of methods will provide the most reliable data. Regardless of the method selected, analyses that account for variation in detection probability among vegetation types will be necessary because most species in our study demonstrated vegetation-dependent detection probabilities

The development of nutrient contents on a new conservation area in the far North of Germany concerning different types of use. A proposal for a sustainable development in nature conservation practice

The present study analyzes a short-term observation of a newly created nature conservation area. The aim was to investigate different effects of grazing by cattle and, otherwise, the frequent mowing on the development of nutrient contents of soils. The results are typical for the strong sandy Weichselian outwash plain in the north of Central Europe (Schleswig-Holstein, Germany). Two neighboring testing areas of different use and sowed with an agricultural grass were observed for more than two years. The first area had been grazed intensively by cattle and the other one had been mowed twice a year. During this time, several nutrients and other soil parameters have been analyzed at regular intervals. Furthermore, we made observations about soil compaction and the succession of vegetation. The results show a stronger reduction especially of nitrogenous nutrients on the mowing area (-25%). In contrast, on the grazing area, the contents of nitrogen doubled during two growing seasons (+125%). However, a high atmospheric input of nitrogen strengthened the result. Less conclusive were the results about the contents of potassium, phosphorus and SOM. Therefore, mowing could be advised, if quick results are required concerning the impoverishment of soils. Furthermore, the development of succession vegetation was quite different on both areas with the number of plant species 12% higher on the grazing area. However, long-term but non-intensive cattle-grazing must still be rated as an excellent method of maintenance for this type of cultural landscape. It corresponds with the centuries-old land-use practice in this type of landscape and promotes high level of biodiversity. Therefore, there is nothing that speaks against non-intensive grazing from the beginning on a newly created nature-protection area within a long-term conception of nature conservation. The removal of A horizons should be avoided as it damages Holocene soil profies and has only short-term effects

Molecular Beam Epitaxy Growth and Characterization of Germanium-Doped Cubic AlxGa1−xN

In cubic (c-)GaN Ge has emerged as a promising alternative to Si for n-type doping, offering the advantage of slightly improved electrical properties. Herein, a study on Ge doping of the ternary alloy c-AlxGa1−xN is presented. Ge-doped c-AlxGa1−xN layers are grown by plasma-assisted molecular beam epitaxy. In two sample series, both the Al mole fraction x and the doping level are varied. The incorporation of Ge is verified by time-of-flight secondary ion mass spectrometry. Ge incorporation and donor concentrations rise exponentially with increasing Ge cell temperature. A maximum donor concentration of 1.4 × 1020 cm−3 is achieved. While the incorporation of Ge is almost independent of x, incorporation of O, which acts as an unintentional donor, increases for higher x. Dislocation densities start increasing when doping levels of around 3 × 1019 cm−3 are exceeded. Also photoluminescence intensities begin to drop at these high doping levels. Optical emission of layers with x > 0.25 is found to originate from a defect level 0.9 eV below the indirect bandgap, which is not related to Ge. In the investigated range 0 ≤ x ≤ 0.6, Ge is a suitable donor in c-AlxGa1−xN up to the low 1019 cm−3 range