High Fluence Chromium and Tungsten Bowtie Nano-antennas

Abstract Nano-antennas are replicas of antennas that operate at radio-frequencies, but with considerably smaller dimensions when compared with their radio frequency counterparts. Noble metals based nano-antennas have the ability to enhance photoinduced phenomena such as localized electric fields, therefore-they have been used in various applications ranging from optical sensing and imaging to performance improvement of solar cells. However, such nano-structures can be damaged in high power applications such as heat resisted magnetic recording, solar thermo-photovoltaics and nano-scale heat transfer systems. Having a small footprint, nano-antennas cannot handle high fluences (energy density per unit area) and are subject to being damaged at adequately high power (some antennas can handle just a few milliwatts). In addition, given that nano-antennas are passive devices driven by external light sources, the potential damage of the antennas limits their use with high power lasers: this liability can be overcome by employing materials with high melting points such as chromium (Cr) and tungsten (W). In this article, we fabricate chromium and tungsten nano-antennas and demonstrate that they can handle 110 and 300 times higher fluence than that of gold (Au) counterpart, while the electric field enhancement is not significantly reduced.

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Analysis on High-Power Seaport LED Luminaire with Uniform Light Distribution Based on Optimized Lens and Heatsink

Applied Sciences ◽

10.3390/app11094035 ◽

2021 ◽

Vol 11 (9) ◽

pp. 4035

Author(s):

Jinsheon Kim ◽

Jeungmo Kang ◽

Woojin Jang

Keyword(s):

Light Source ◽

High Power ◽

Heat Dissipation ◽

Light Emitting Diode ◽

Light Distribution ◽

Light Sources ◽

Led Light ◽

High Power Led ◽

Distribution Requirement ◽

Lighting Application

In the case of light-emitting diode (LED) seaport luminaires, they should be designed in consideration of glare, average illuminance, and overall uniformity. Although it is possible to implement light distribution through auxiliary devices such as reflectors, it means increasing the weight and size of the luminaire, which reduces the feasibility. Considering the special environment of seaport luminaires, which are installed at a height of 30 m or more, it is necessary to reduce the weight of the device, facilitate replacement, and secure a light source with a long life. In this paper, an optimized lens design was investigated to provide uniform light distribution to meet the requirement in the seaport lighting application. Four types of lens were designed and fabricated to verify the uniform light distribution requirement for the seaport lighting application. Using numerical analysis, we optimized the lens that provides the required minimum overall uniformity for the seaport lighting application. A theoretical analysis for the heatsink structure and shape were conducted to reduce the heat from the high-power LED light sources up to 250 W. As a result of these analyses on the heat dissipation characteristics of the high-power LED light source used in the LED seaport luminaire, the heatsink with hexagonal-shape fins shows the best heat dissipation effect. Finally, a prototype LED seaport luminaire with an optimized lens and heat sink was fabricated and tested in a real seaport environment. The light distribution characteristics of this prototype LED seaport luminaire were compared with a commercial high-pressure sodium luminaire and metal halide luminaire.

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Colossal Terahertz Field Enhancement in Slant Nano-Antennas

2020 45th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) ◽

10.1109/irmmw-thz46771.2020.9370851 ◽

2020 ◽

Author(s):

Hyeong Seok Yun ◽

Dai-Sik Kim

Keyword(s):

Field Enhancement ◽

Nano Antennas

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System efficiency of laser-based white light

Advanced Optical Technologies ◽

10.1515/aot-2014-0048 ◽

2014 ◽

Vol 3 (5-6) ◽

Cited By ~ 1

Author(s):

Roland Lachmayer ◽

Alexander Wolf ◽

Gerolf Kloppenburg

Keyword(s):

Thermal Management ◽

White Light ◽

High Power ◽

Laser Diodes ◽

Light Sources ◽

System Efficiency ◽

Light Emitting ◽

Scale Down ◽

Color Rendering ◽

Product Weight

AbstractFor many lighting applications, light-emitting diodes (LEDs) are replacing traditional light sources providing the possibility for smart and efficient systems as well as a reduction in the product weight. A next step in this development is the integration of laser-based light sources to increase luminance and to further scale down the optics possibly leading to a reduction of necessary resources. This article reviews the possibilities and challenges arising from the use of laser diodes especially compared to current high-power LED systems in terms of efficiency, color-rendering properties, and thermal management.

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Reliability of High-Power Light Emitting Diode Attached With Different Thermal Interface Materials

Journal of Electronic Packaging ◽

10.1115/1.4002299 ◽

2010 ◽

Vol 132 (3) ◽

Cited By ~ 23

Author(s):

Xin Li ◽

Xu Chen ◽

Guo-Quan Lu

Keyword(s):

High Power ◽

Heat Dissipation ◽

Light Emitting Diode ◽

Temperature Cycling ◽

Fluorescent Light ◽

Light Sources ◽

Light Emitting ◽

Die Attach ◽

Nanosilver Paste ◽

Interconnection Material

As a solid electroluminescent source, white light emitting diode (LED) has entered a practical stage and become an alternative to replace incandescent and fluorescent light sources. However, due to the increasing integration and miniaturization of LED chips, heat flux inside the chip is also increasing, which puts the packaging into the position to meet higher requirements of heat dissipation. In this study, a new interconnection material—nanosilver paste is used for the LED chip packaging to pursue a better optical performance, since high thermal conductivity of this material can help improve the efficiency of heat dissipation for the LED chip. The bonding ability of this new die-attach material is evaluated by their bonding strength. Moreover, high-power LED modules connected with nanosilver paste, Sn3Ag0.5Cu solder, and silver epoxy are aged under hygrothermal aging and temperature cycling tests. The performances of these LED modules are tested at different aging time. The results show that LED modules sintered with nanosilver paste have the best performance and stability.

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The Impact of Inhomogeneities in the Phosphor Distribution on the Device Performance of Phosphor-Converted High-Power White LED Light Sources

Journal of Lightwave Technology ◽

10.1109/jlt.2010.2079316 ◽

2010 ◽

Cited By ~ 31

Author(s):

C Sommer ◽

F Reil ◽

J R Krenn ◽

P Hartmann ◽

P Pachler ◽

...

Keyword(s):

High Power ◽

Device Performance ◽

Light Sources ◽

White Led ◽

Led Light ◽

The Impact

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Effect of Light-Sources and Thicknesses of Composite Onlays on Micro-Hardness of Luting Composites

Materials ◽

10.3390/ma14226849 ◽

2021 ◽

Vol 14 (22) ◽

pp. 6849

Author(s):

Francesco De Angelis ◽

Mirco Vadini ◽

Mario Capogreco ◽

Camillo D’Arcangelo ◽

Maurizio D’Amario

Keyword(s):

High Power ◽

Resin Composite ◽

Composite Layer ◽

Resin Cement ◽

Specimen Thickness ◽

Light Sources ◽

Curing Time ◽

Resin Cements ◽

Halogen Light ◽

Light Curing

The aim of this study was to compare three different light-curing-units (LCUs) and determine their effectiveness in the adhesive cementation of indirect composite restorations when a light-curing resin cement is used. Two resin composites were selected: Enamel Plus HRI (Micerium) and AURA (SDI). Three thicknesses (3 mm, 4 mm and 5 mm) were produced and applied as overlays and underlays for each resin composite. A standardized composite layer was placed between underlay and overlay surfaces. Light curing of the resin-based luting composites was attained through the overlay filters using LCUs for different exposure times. All specimens were allocated to experimental groups according to the overlay thickness, curing unit and curing time. Vickers Hardness (VH) notches were carried out on each specimen. Data were statistically evaluated. The curing unit, curing time and overlay thickness were significant factors capable of influencing VH values. The results showed significantly decreased VH values with increasing specimen thickness (p < 0.05). Significant differences in VH values were found amongst the LCUs for the various exposure times (p < 0.05). According to the results, a time of cure shorter than 80 s (with a conventional quartz–tungsten–halogen LCU) or shorter than 40 s (with a high-power light-emitting diode (LED) LCU) is not recommended. The only subgroup achieving clinically acceptable VH values after a short 20 s curing time included the 3 mm-thick overlays made out of the AURA composite, when the high-power LED LCU unit was used (VH 51.0). Composite thickness has an intense effect on polymerization. In clinical practice, light-cured resin cements may result in insufficient polymerization for high thickness and inadequate times. High-intensity curing lights can attain the sufficient polymerization of resin cements through overlays in a significantly shorter time than conventional halogen light.

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High power mid-infrared supercontiuum light sources based on fluorotellurite glass fibers (invited)

Infrared and Laser Engineering ◽

10.3788/irla201847.0803004 ◽

2018 ◽

Vol 47 (8) ◽

pp. 803004

Author(s):

贾志旭 Jia Zhixu ◽

姚传飞 Yao Chuanfei ◽

李真睿 Li Zhenrui ◽

贾世杰 Jia Shijie ◽

赵志鹏 Zhao Zhipeng ◽

...

Keyword(s):

High Power ◽

Glass Fibers ◽

Light Sources ◽

Mid Infrared

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Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.16.40 ◽

2020 ◽

Vol 16 ◽

pp. 415-444 ◽

Cited By ~ 7

Author(s):

Bernd Strehmel ◽

Christian Schmitz ◽

Ceren Kütahya ◽

Yulian Pang ◽

Anke Drewitz ◽

...

Keyword(s):

Electrochemical Properties ◽

High Power ◽

Near Infrared ◽

New Technologies ◽

Light Sources ◽

Hydrophobic Properties ◽

On Demand ◽

Nir Light ◽

Photothermal Treatment ◽

End Groups

Cyanines derived from heptamethines were mainly discussed regarding their functionalization to broaden the solubility in different surroundings exhibiting either hydrophilic or hydrophobic properties and to tailor made the ΔG et photopysical properties with respect to absorption and fluorescence. Electrochemical properties were additionally considered for some selected examples. The cyanines chosen comprised as end groups either indolenine, benzo[e]- or benzo[cd]indolium pattern, which facilitated to shift the absorption between 750–1000 nm. This enabled their use in applications with light sources emitting in the near-infrared (NIR) region selected from high power LEDs or lasers with line-shaped focus. The absorbers considered were discussed regarding their function as sensitizer for applications related to Chemistry 4.0 standards. These were mainly photopolymer coatings, which can be found for applications in the graphic industry or to protect selected substrates. The huge release of heat on demand upon turning ON or OFF the NIR light source enables them for photothermal treatment in processes requesting heat to initiate either chemical (activated reactions) or physical (melting, evaporation) events.

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