Gold nanostars for random lasing enhancement

Ziegler, Johannes; Djiango, Martin; Vidal, Cynthia; Hrelescu, Calin; Klar, Thomas A.

doi:10.1364/oe.23.015152

Cited by 66 publications

(43 citation statements)

References 34 publications

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“…In plasmonics, field enhancement effects near metallic nanostructures are utilized to strengthen the light-matter interaction and to miniaturize optical or optoelectronic functionality. Most prominently, plasmonic resonances of metal nanoparticles (NPs) have been used for a plethora of applications and are well understood both experimentally and theoretically [1][2][3][4][5][6][7][8][9][10][11] . However NPs feature some fundamental limitations, e.g., concerning their minimal damping rates or quality (Q) factors 10 .…”

Section: Introductionmentioning

confidence: 99%

Silver nanowires with optimized silica coating as versatile plasmonic resonators

Rothe

Zhao

Kewes

et al. 2019

Sci Rep

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Metal nanoparticles are the most frequently used nanostructures in plasmonics. However, besides nanoparticles, metal nanowires feature several advantages for applications. Their elongation offers a larger interaction volume, their resonances can reach higher quality factors, and their mode structure provides better coupling into integrated hybrid dielectric-plasmonic circuits. It is crucial though, to control the distance of the wire to a supporting substrate, to another metal layer or to active materials with sub-nanometer precision. A dielectric coating can be utilized for distance control, but it must not degrade the plasmonic properties. In this paper, we introduce a controlled synthesis and coating approach for silver nanowires to fulfill these demands. We synthesize and characterize silver nanowires of around 70 nm in diameter. These nanowires are coated with nm-sized silica shells using a modified Stöber method to achieve a homogeneous and smooth surface quality. We use transmission electron microscopy, dark-field microscopy and electron-energy loss spectroscopy to study morphology and plasmonic resonances of individual nanowires and quantify the influence of the silica coating. Thorough numerical simulations support the experimental findings showing that the coating does not deteriorate the plasmonic properties and thus introduce silver nanowires as usable building blocks for integrated hybrid plasmonic systems.

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Section: Introductionmentioning

confidence: 99%

Silver nanowires with optimized silica coating as versatile plasmonic resonators

Rothe

Zhao

Kewes

et al. 2019

Sci Rep

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“…For enhancing the nonlinear SHG on the micrometer scale, the optical field intensity of the pumping light becomes more critical. To realize a high optical‐field density on a small spatial scale, metal surface plasmons were introduced to improve the nonlinear light–matter interaction . Accordingly, 20 nm thick Ag films were deposited on two sapphire substrates.…”

Section: Resultsmentioning

confidence: 99%

“…For the MW on the Ag films, no significant intensity enhancement can be observed (blue line). Generally, the surface plasmon resonance cannot be produced on a bare homogeneous metal film . Therefore, the enhancement effect of the Ag film plays a weak role in the nonlinear SHG.…”

Section: Resultsmentioning

confidence: 99%

Enhanced Second‐Harmonic Generation in a Single Microwire Based on Localized Surface Plasmon

Zhu

Chen

et al. 2019

Physica Status Solidi (b)

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The properties of enhanced second-harmonic generation (SHG) in microwires (MWs) through surface plasmonics have been investigated comprehensively. Here, the high Q-factor hexagonal microcavity of a single MW can significantly confine the fundamental frequency of light. Moreover, randomly distributed Ag nanoparticles are fabricated on a template plate, which is used to enhance the SHG through localized surface plasmon (LSP). Compared with a bare MW, the intensity of the SHG based on LSP can be enhanced twofold at room temperature. It is seen that the LSP effect on SHG is sensitive to temperature, and the enhancement ratio partly increases linearly with decreasing temperature, which can be explained by the dependence of the metal dielectric permittivity on the temperature according to the Drude model.

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“…In this scenario, macroscopic laser cavities such as the Fabry–Perot cavities and ring resonators discussed above may not be applicable. In contrast, the random laser [47,48] and plasmonic laser [49] offer a possible tool to realize lasing at the microscopic and nanoscopic scales. However, it should be noted that those types of laser cavities usually have much lower Q -factors, which may require higher ICG concentrations and pump intensities.…”

Section: Discussionmentioning

confidence: 99%

Lasing in blood

Chen

Fan

2016

Optica

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Indocyanine green (ICG) is the only near-infrared dye approved by the U.S. Food and Drug Administration for clinical use. When injected in blood, ICG binds primarily to plasma proteins and lipoproteins, resulting in enhanced fluorescence. Recently, the optofluidic laser has emerged as a novel tool in bio-analysis. Laser emission has advantages over fluorescence in signal amplification, narrow linewidth, and strong intensity, leading to orders of magnitude increase in detection sensitivity and imaging contrast. Here we successfully demonstrate, to the best of our knowledge, the first ICG lasing in human serum and whole blood with the clinical ICG concentrations and the pump intensity far below the clinically permissible level. Furthermore, we systematically study ICG laser emission within each major serological component (albumins, globulins, and lipoproteins) and reveal the critical elements and conditions responsible for lasing. Our work marks a critical step toward eventual clinical and biomedical applications of optofluidic lasers using FDA approved fluorophores, which may complement or even supersede conventional fluorescence-based sensing and imaging.

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Gold nanostars for random lasing enhancement

Cited by 66 publications

References 34 publications

Silver nanowires with optimized silica coating as versatile plasmonic resonators

Silver nanowires with optimized silica coating as versatile plasmonic resonators

Enhanced Second‐Harmonic Generation in a Single Microwire Based on Localized Surface Plasmon

Lasing in blood

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