Plasmonics in semiconductors and in Ag submicron wires and graphene

Some 50 years ago discussions of plasmonics in semiconductors lead to many new concepts such as travelling domain structures with applications leading even to logic systems. Now plasmonics of submicron wires of Ag and graphene bring new device concepts for the fabrication of compact THz sources and optical focusing of the beat signal into the active area. Here as an experimental example such new opportunities are involved with compact THz sources based on optical laser mixing. They include resonant plasmonic structures at THz and optical frequencies to locally enhance the electromagnetic fields at THz as well as optical frequencies by the combination of semiconductor-graphene plasmons respectively by the semiconductor-metal-nanostructure plasmons. Of particular interest is the usage of graphene, which is optically transmitting and which is either a semimetal or can be transformed into a semiconductor by reducing the width of its strips to about 30 nm, opening a band gap in the meV to tens of the meV range. A successful experimental structure for continuous-wave THz photomixing is fabricated using 1D and 2D nanocontacts either on low-temperature-grown (LTG) GaAs or on nitrogen ion-implanted (N+i) GaAs and graphene sheets. The overlaying 1D and 2D nanocontacts were formed by silver nanowires with a diameter of 60 or 120 nm. They can handle currents of >10 and >30 mA, respectively, without electromigration enabling reliably high photocurrents and field enhancement at THz frequencies by plasmonic effects. The nanomaterial structurization in connection with present-day plasmonic applications is now to be discussed in a similar manner as past opportunities with semiconductor plasmonics.

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Luminescent tracks of high-energy photoemitted electrons accelerated by plasmonic fields

Nanophotonics ◽

10.1515/nanoph-2015-0029 ◽

2015 ◽

Vol 4 (4) ◽

pp. 511-519

Author(s):

Marcel Di Vece ◽

Giorgos Giannakoudakis ◽

Astrid Bjørkøy ◽

Wingjohn Tang

Keyword(s):

Confocal Microscopy ◽

State Of The Art ◽

Field Enhancement ◽

Optical Excitation ◽

High Energy ◽

Intense Laser ◽

Electron Interaction ◽

Intense Laser Pulse ◽

Local Field Enhancement ◽

Metal Nanostructure

AbstractThe emission of an electron from a metal nanostructure under illumination and its subsequent acceleration in a plasmonic field forms a platform to extend these phenomena to deposited nanoparticles, which can be studied by state-of-the-art confocal microscopy combined with femtosecond optical excitation. The emitted and accelerated electrons leave defect tracks in the immersion oil, which can be revealed by thermoluminescence. These photographic tracks are read out with the confocal microscope and have a maximum length of about 80 μm, which corresponds to a kinetic energy of about 100 keV. This energy is consistent with the energy provided by the intense laser pulse combined with plasmonic local field enhancement. The results are discussed within the context of the rescattering model by which electrons acquire more energy. The visualization of electron tracks originating from plasmonic field enhancement around a gold nanoparticle opens a new way to study with confocal microscopy both the plasmonic properties of metal nano objects as well as high energy electron interaction with matter.

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Development of compact continuous-wave terahertz (THz) sources by photoconductive mixing

Materials Challenges and Testing for Supply of Energy and Resources ◽

10.1007/978-3-642-23348-7_22 ◽

2011 ◽

pp. 245-250

Author(s):

H. Tanoto ◽

J. H. Teng ◽

Q. Y. Wu ◽

M. Sun ◽

Z. N. Chen ◽

...

Keyword(s):

Continuous Wave ◽

Thz Sources

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Imaging Upconversion from NaYF4:Er:Yb Nanoparticles on Au and Ag Nanostructured Substrates

MRS Proceedings ◽

10.1557/opl.2011.997 ◽

2011 ◽

Vol 1342 ◽

Author(s):

Lanlan Zhong ◽

QuocAnh Luu ◽

Hari P. Paudel ◽

Khadijeh Bayat ◽

Mahdi Farrokh Baroughi ◽

...

Keyword(s):

Near Infrared ◽

Imaging System ◽

Silver Nanowires ◽

Field Enhancement ◽

Nano Particles ◽

Wide Field ◽

Solar Concentrators ◽

Spatially Resolved ◽

Luminescent Solar Concentrators ◽

Spectrally Resolved

ABSTRACTNear-infrared-to-visible upconversion materials have many promising applications, including use in luminescent solar concentrators, in next-generation displays, and as biological labels. NaYF4 nano-particles doped with Yb and Er exhibit efficient upconversion and are easily deployed in these applications. It is known that a rough metal surface may increase the yield of fluorescence of a nearby fluorophore, by local field enhancement due to plasmonic resonances, and by modification of the radiative rate(s) of the fluorophore. Thus, properly chosen metallic nanostructures can potentially increase the upconversion efficiency of lanthanide-doped nanoparticles, yet the optimal design of these nanostructures is still an active area of research. In our experiments, we use a spectroscopic imaging system to study the upconversion efficiency of NaYF4: Er3+/ Yb3+ through spatially-resolved upconversion spectra, using a custom-built scanning confocal microscope system with infra-red excitation, and wide-field fluorescence imaging. We present spectrally-resolved upconversion images of NaYF4:Yb3+/Er3+ nanoparticles on plasmonic substrates, including silver nanowires and patterned substrates of gold and silver, which show localized regions (∼ 1μm) of relatively stronger intensity and modified upconversion spectra, and compare these to wide-field fluorescence images of samples with and without plasmonic substrates.

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The Principle of the New Fiber-Delivering Device for Friction Spinning

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.287-290.2602 ◽

2011 ◽

Vol 287-290 ◽

pp. 2602-2605

Author(s):

Jin Quan Wang ◽

Li Jun Qu ◽

Guo Hua Chen

Keyword(s):

Open Space ◽

New Device ◽

New Concepts

A new flats-delivering device has been invented to improve the straight and parallel alevel of fibers in a friction spinning fram. The principle of the friction spinning based on the flats-delivering device called tapered pipe and open-space flats has been investigated. New concepts of the “curvilinear-transmitting” and the “parallel condensing” have been suggested to explain the theory of the new divice. The transmission experiments of this improved device has also been reported. It was found that this new device could achieve the effect of straighten and paralleled fibers when fibers sucked into the v-zone of the dust drums in a friction spinning fram.

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Room temperature continuous wave, monolithic tunable THz sources based on highly efficient mid-infrared quantum cascade lasers

Scientific Reports ◽

10.1038/srep23595 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 62

Author(s):

Quanyong Lu ◽

Donghai Wu ◽

Saumya Sengupta ◽

Steven Slivken ◽

Manijeh Razeghi

Keyword(s):

Room Temperature ◽

Continuous Wave ◽

Quantum Cascade Lasers ◽

Mid Infrared ◽

Quantum Cascade ◽

Highly Efficient ◽

Thz Sources ◽

Cascade Lasers

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Nano-enhanced optical gene delivery to retinal degenerated mice

10.1101/509349 ◽

2019 ◽

Author(s):

Subrata Batabyal ◽

Sivakumar Gajjeraman ◽

Sulagna Bhattacharya ◽

Weldon Wright ◽

Samarendra Mohanty

Keyword(s):

Gene Delivery ◽

Targeted Delivery ◽

Near Infrared ◽

Continuous Wave ◽

Inflammatory Responses ◽

Field Enhancement ◽

Age Related Macular Degeneration ◽

Age Related ◽

Low Efficiency

ABSTRACTThe efficient and targeted delivery of genes and other impermeable therapeutic molecules into retinal cells is of immense importance for therapy of various visual disorders. Traditional methods for gene delivery require viral transfection, or chemical methods that suffer from one or many drawbacks such as invasiveness, low efficiency, lack of spatially targeted delivery, and can generally have deleterious effects such as unexpected inflammatory responses and immunological reactions. Here, we introduce a continuous wave near-infrared laser-based Nano-enhanced Optical Delivery (NOD) method for spatially controlled delivery of opsin-encoding genes into retina in-vivo. In this method, the optical field enhancement by gold nanorods is utilized to transiently permeabilize cell membrane enabling delivery of exogenous impermeable molecules to nanorod-binding cells in laser-irradiated regions. The successful delivery and expression of opsin in targeted retina after in-vivo NOD in the mice models of retinal degeneration opens new vista for re-photosensitizing retina with geographic atrophies as in dry age-related macular degeneration (AMD).

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Introductory remarks

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences ◽

10.1098/rsta.1980.0244 ◽

1980 ◽

Vol 298 (1439) ◽

pp. 211-215 ◽

Cited By ~ 3

Keyword(s):

Continuous Wave ◽

Semiconductor Diode ◽

Electromagnetic Spectrum ◽

X Rays ◽

Short Pulses ◽

Light Pulses ◽

Semiconductor Diode Lasers ◽

New Concepts ◽

Subpicosecond Pulses ◽

Physical And Chemical

The first day of this Discussion Meeting is mainly devoted to ultra-short laser sources and the methods of measurement of picosecond and subpicosecond pulses of radiation over the electromagnetic spectrum from X-rays to the infrared. The last decade has seen dramatic advances in the understanding of the complex physical and chemical processes occurring in mode-locked lasers and in the interactions, linear and nonlinear, with matter of the ultra-short light pulses so produced. The flashlamp-pumped frequency-tunable dye laser has played a key role in these advances. It provided the shortest and most controllable pulses for the development of time-resolving instruments and, later, was an experimental model for the detailed measurements that eventually led to the elucidation of the mechanisms by which ultra-short pulses evolve in a mode-locked laser from the initial fluorescence intensity fluctuations (see Bradley & New (1974) for references). These new concepts, in turn, were applied to the development of mode-locked continuous wave (c.w.) dye lasers and, more recently, to mode-locked semiconductor diode lasers. Both of these types of c.w. lasers will be discussed in some of the following papers.

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Ultra-narrow-linewidth continuous-wave THz sources based on multiplier chains

Applied Physics B ◽

10.1007/s00340-008-3279-9 ◽

2008 ◽

Vol 95 (1) ◽

pp. 55-61 ◽

Cited By ~ 16

Author(s):

S. Schiller ◽

B. Roth ◽

F. Lewen ◽

O. Ricken ◽

M. C. Wiedner

Keyword(s):

Continuous Wave ◽

Narrow Linewidth ◽

Thz Sources

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Ultra-narrowband and highly-directional THz thermal emitters based on the bound state in the continuum

Nanophotonics ◽

10.1515/nanoph-2021-0380 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Kaili Sun ◽

Zongshan Zhao ◽

Yangjian Cai ◽

Uriel Levy ◽

Zhanghua Han

Keyword(s):

Continuous Wave ◽

Bound State ◽

New Physics ◽

High Resistivity ◽

Wave Form ◽

Practical Applications ◽

Thermal Emitters ◽

Thermal Emitter ◽

Thz Sources ◽

The Continuum

Abstract The development of novel and cost-effective THz emitters, with properties superior to current THz sources, is an active and important field of research. In this work, we propose and numerically demonstrate a simple yet effective approach of realizing terahertz sources working in continuous-wave form, by incorporating the new physics of bound state in the continuum (BIC) into thermal emitters. By deliberately designing the structure of slotted disk array made of high-resistivity silicon on top of a low index dielectric buffer layer supported by a conducting substrate, a quasi-BIC mode with ultra-high quality factor (∼104) can be supported. Our results reveal that the structure can operate as an efficient terahertz thermal emitter with near-unity emissivity and ultranarrow bandwidth. For example, an emitter working at 1.3914 THz with an ultranarrow linewidth less than 130 MHz, which is roughly 4 orders of magnitude smaller than that obtained from a metallic metamaterial-based thermal emitter, is shown. In addition to its high monochromaticity, this novel emitter has additional important advantages including high directionality and linear polarization, which makes it a promising candidate as the new generation of THz sources. It holds a great potential for practical applications where high spectral resolving capability is required.

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