Dependence of Q Factor on Surface Roughness in a Plasmonic Cavity

Kim, Yoon Ho; Kwon, Soon-Hong; Ee, Ho Seok; Hwang, Yongsop; No, You Shin; Park, Hong Gyu

doi:10.3807/josk.2016.20.1.188

Cited by 7 publications

(6 citation statements)

References 15 publications

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“…The Si/Au core/shell NW design thus offers a good quality plasmon resonance, as prior reports of the Q factors of plasmon modes in metal/semiconductor hybrid nanostructures have yielded values ranging from approximately 10 to 250. 56,57 Experimental extinction measurements were performed using a home-built, polarization-controlled extinction microscope described previously 14 by transferring core/shell NWs from the growth substrate to microscopy slides. For experimental analysis, we targeted a NW with a large diameter and thin shell (d = 400 nm, t = 30 nm) and a small-diameter NW (d = 150 nm) with thin (t = 30 nm) and thick (t = 50 nm) Au shells.…”

Section: Resultsmentioning

confidence: 99%

“…The experimental values of Q tot are 3−4 times lower than the theoretical values determined by TCMT fits of the simulated spectra. Considering the roughness of the Au shell, 57 the presence of oxide and organic layers at the Si/Au interface, finite beam spot size, and finite NW lengths that could introduce additional losses and changes to the resonances, we consider these Q factors to be in reasonable agreement with simulations. Moreover, the thicker Au shell produces a Q factor ∼50% higher, in agreement with expectations from simulations.…”

Section: Resultsmentioning

confidence: 99%

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Epitaxially Grown Silicon Nanowires with a Gold Molecular Adhesion Layer for Core/Shell Structures with Compact Mie and Plasmon Resonances

Murphey,

Park,

Kim

et al. 2023

ACS Nano

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Noble-metal plasmonic nanostructures have attracted much attention because they can support deep-subwavelength optical resonances, yet their performance tends to be limited by high Ohmic absorption losses. In comparison, high-index dielectric materials can support low-loss optical resonances but do not tend to yield the same subwavelength optical confinement. Here, we combine these two approaches and examine the dielectric-plasmonic resonances in dielectric/metal core/shell nanowires. Si nanowires were grown epitaxially from (111) substrates, and direct deposition of Au on these structures by physical vapor deposition yielded nonconformal Au islands. However, by introduction of a molecular adhesion layer prior to deposition, cylindrical Si/Au core/shell nanostructures with conformal metal shells were successfully fabricated. Examining these structures as optical cavities using both optical simulations and experimental extinction measurements, we found that the structures support Mie resonances with quality factors enhanced up to ∼30 times compared with pure dielectric structures and plasmon resonances with optical confinement enhanced up to ∼5 times compared with pure metallic structures. Interestingly, extinction spectra of both Mie and plasmon resonances yield Fano line shapes, whose manifestation can be attributed to the combination of high quality factor resonances, Mie-plasmon coupling, and phase delay of the background optical field. This work demonstrates a bottom-up synthetic method for the production of freestanding, cylindrically symmetric semiconductor/metal core/shell nanowires that enables the efficient trapping of light on deep-subwavelength length scales for varied applications in photonics and optoelectronics.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Epitaxially Grown Silicon Nanowires with a Gold Molecular Adhesion Layer for Core/Shell Structures with Compact Mie and Plasmon Resonances

Murphey,

Park,

Kim

et al. 2023

ACS Nano

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“…To simulate the effects of surface roughness of the sidewall, we generated a surface with random roughness following the Gaussian distribution and a Gaussian lateral correlation function. [ 38–40 ] The root‐mean‐square (rms) height and correlation length ( L ) of the surface are fixed at 10 and 20 nm, typical of the surface roughness for InP with inductively coupled plasma (ICP) etching. [ 41 ] The results of simulation in this case are summarized in Figures 3e.…”

Section: Resultsmentioning

confidence: 99%

Room‐Temperature Low‐Threshold Plasmonic Nanolaser through Mode‐Tailoring at Communication Wavelengths

Zhang

et al. 2022

Laser & Photonics Reviews

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Plasmonic nanolasers have shown unique potential for on-chip optical interconnects at optical communication wavelengths because of their ultra-small physical volumes beyond the diffraction limit. However, the high threshold and associated power consumption are key remaining challenges due to the long-recognized intrinsic plasmonic absorption and extrinsic losses related to the inevitable fabrication imperfections and the resulting rough surfaces or interfaces. This article demonstrates a new threshold-reduction strategy in a silver-cup plasmonic nanolaser by selectively confining plasmonic modes at the high-quality naturally cleaved surfaces at the bottom, while avoiding the rough etched surfaces of the sidewall. Through size control and modal design, lasing preferentially occurs via the bottom whispering gallery plasmonic mode with a large quality factor, small modal volume, and robust performance largely immune to fabrication imperfections. The nanolaser has a subwavelength volume of 0.02𝝀 3 near 𝝀 = 1.55 µm with a record-low threshold of 20.1 kW cm −2 for a near-infrared plasmonic nanolaser at room temperature under optical pumping. Importantly, the laser becomes the first near-infrared plasmonic nanolaser to meet the power-consumption requirement of less than 10 fJ bit −1 , providing one of the rarely available on-chip sources with a small footprint and low power consumption for the photonic integrated circuits.

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“…The particle sizes on the metal surfaces can be decreased with several elaborate fabrication techniques, such as the deposition parameter control [ 22 ], template stripping method [ 21 , 23 ], and thermo-assisted spin coating [ 24 ]. With increasing roughness, the Ohmic absorption loss and scattering loss in the metal surfaces increases [ 25 , 26 ]. Therefore, the directional scattering light in plasmonic devices can be degraded, and the sensing performance can be decreased.…”

Section: Methodsmentioning

confidence: 99%

Hydrogen Sensor: Detecting Far-Field Scattering of Nano-Blocks (Mg, Ag, and Pd)

Shin

Lee

Nam

et al. 2020

Sensors

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Hydrogen sensor technologies have been rapidly developing. For effective and safe sensing, we proposed a hydrogen sensor composed of magnesium (Mg), silver (Ag), and palladium (Pd) nano-blocks that overcomes the spectral resolution limit. This sensor exploited the properties of Mg and Pd when absorbing hydrogen. Mg became a dielectric material, and the atomic lattice of Pd expanded. These properties led to changes in the plasmonic gap mode between the nano-blocks. Owing to the changing gap mode, the far-field scattering pattern significantly changed with the hydrogen concentration. Thus, sensing the hydrogen concentration was able to be achieved simply by detecting the far-field intensity at a certain angle for incident light with a specific wavelength.

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Dependence of Q Factor on Surface Roughness in a Plasmonic Cavity

Cited by 7 publications

References 15 publications

Epitaxially Grown Silicon Nanowires with a Gold Molecular Adhesion Layer for Core/Shell Structures with Compact Mie and Plasmon Resonances

Epitaxially Grown Silicon Nanowires with a Gold Molecular Adhesion Layer for Core/Shell Structures with Compact Mie and Plasmon Resonances

Room‐Temperature Low‐Threshold Plasmonic Nanolaser through Mode‐Tailoring at Communication Wavelengths

Hydrogen Sensor: Detecting Far-Field Scattering of Nano-Blocks (Mg, Ag, and Pd)

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