Plasmonic mode conversion in individual tilted 3D nanostructures

Nanoscale ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 5429-5440 ◽  
Author(s):  
Christoph Dreser ◽  
Dominik A. Gollmer ◽  
Godofredo Bautista ◽  
Xiaorun Zang ◽  
Dieter P. Kern ◽  
...  
Keyword(s):  
Electric Field ◽  
Mode Conversion ◽  
Near Field ◽  
Field Enhancement ◽  
Plasmonic Nanostructures ◽  
Plasmonic Mode ◽  
3D Nanostructures ◽  
Out Of Plane

Mode conversion in individual asymmetric plasmonic nanostructures enables out-of-plane near-field enhancement with only in-plane electric field components.

scholarly journals Plasmonic interference modulation for broadband nanofocusing

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Shaobo Li ◽  
Shuming Yang ◽  
Fei Wang ◽  
Qiang Liu ◽  
Biyao Cheng ◽  
...  
Keyword(s):  
Near Field ◽  
Three Dimensional ◽  
Field Enhancement ◽  
Incident Beam ◽  
Plasmonic Mode ◽  
Resonant Structures ◽  
Interference Modulation ◽  
Near Field Imaging ◽  
Linearly Polarized ◽  
Radially Polarized

Abstract Metallic plasmonic probes have been successfully applied in near-field imaging, nanolithography, and Raman enhanced spectroscopy because of their ability to squeeze light into nanoscale and provide significant electric field enhancement. Most of these probes rely on nanometric alignment of incident beam and resonant structures with limited spectral bandwidth. This paper proposes and experimentally demonstrates an asymmetric fiber tip for broadband interference nanofocusing within its full optical wavelengths (500–800 nm) at the nanotip with 10 nm apex. The asymmetric geometry consisting of two semicircular slits rotates plasmonic polarization and converts the linearly polarized plasmonic mode to the radially polarized plasmonic mode when the linearly polarized beam couples to the optical fiber. The three-dimensional plasmonic modulation induces circumference interference and nanofocus of surface plasmons, which is significantly different from the nanofocusing through plasmon propagation and plasmon evolution. The plasmonic interference modulation provides fundamental insights into the plasmon engineering and has important applications in plasmon nanophotonic technologies.

scholarly journals Metal–dielectric hybrid nanoantennas for efficient frequency conversion at the anapole mode

2018 ◽  
Vol 9 ◽  
pp. 2306-2314 ◽  
Author(s):  
Valerio F Gili ◽  
Lavinia Ghirardini ◽  
Davide Rocco ◽  
Giuseppe Marino ◽  
Ivan Favero ◽  
...  
Keyword(s):  
Frequency Conversion ◽  
Near Infrared ◽  
Strong Field ◽  
Second Harmonic ◽  
Near Field ◽  
Field Enhancement ◽  
High Refractive Index ◽  
Plasmonic Nanostructures ◽  
Ohmic Losses ◽  
Order Of Magnitude

Background: Dielectric nanoantennas have recently emerged as an alternative solution to plasmonics for nonlinear light manipulation at the nanoscale, thanks to the magnetic and electric resonances, the strong nonlinearities, and the low ohmic losses characterizing high refractive-index materials in the visible/near-infrared (NIR) region of the spectrum. In this frame, AlGaAs nanoantennas demonstrated to be extremely efficient sources of second harmonic radiation. In particular, the nonlinear polarization of an optical system pumped at the anapole mode can be potentially boosted, due to both the strong dip in the scattering spectrum and the near-field enhancement, which are characteristic of this mode. Plasmonic nanostructures, on the other hand, remain the most promising solution to achieve strong local field confinement, especially in the NIR, where metals such as gold display relatively low losses. Results: We present a nonlinear hybrid antenna based on an AlGaAs nanopillar surrounded by a gold ring, which merges in a single platform the strong field confinement typically produced by plasmonic antennas with the high nonlinearity and low loss characteristics of dielectric nanoantennas. This platform allows enhancing the coupling of light to the nanopillar at coincidence with the anapole mode, hence boosting both second- and third-harmonic generation conversion efficiencies. More than one order of magnitude enhancement factors are measured for both processes with respect to the isolated structure. Conclusion: The present results reveal the possibility to achieve tuneable metamixers and higher resolution in nonlinear sensing and spectroscopy, by means of improved both pump coupling and emission efficiency due to the excitation of the anapole mode enhanced by the plasmonic nanoantenna.

scholarly journals Interplay between out-of-plane magnetic plasmon and lattice resonance for modified resonance lineshape and near-field enhancement in double nanoparticles array

2013 ◽  
Vol 22 (12) ◽  
pp. 127802 ◽  
Author(s):  
Pei Ding ◽  
Jun-Qiao Wang ◽  
Jin-Na He ◽  
Chun-Zhen Fan ◽  
Gen-Wang Cai ◽  
...  
Keyword(s):  
Near Field ◽  
Field Enhancement ◽  
Out Of Plane ◽  
Magnetic Plasmon

scholarly journals Grating-assisted coupling enhancing plasmonic tip nanofocusing illuminated via radial vector beam

Nanophotonics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 2303-2311 ◽  
Author(s):  
Fanfan Lu ◽  
Wending Zhang ◽  
Jiachen Zhang ◽  
Min Liu ◽  
Lu Zhang ◽  
...  
Keyword(s):  
Electric Field ◽  
Near Field ◽  
Numerical Aperture ◽  
Field Enhancement ◽  
Super Resolution ◽  
Decisive Role ◽  
Excitation Wavelength ◽  
Label Free ◽  
Vector Beam ◽  
Simulation Results

AbstractTip-enhanced Raman spectroscopy (TERS) is a very useful method to achieve label-free and super-resolution imaging, and the plasmonic tip nanofocusing plays a decisive role for TERS performance. Here, we present a method to enhance the nanofocusing characteristic of a plasmonic tip integrated in a grating near the tip apex. Simulation results show that the grating near the tip apex can significantly improve the electric field intensity of the nanofocusing field compared with a conventional bare tip, under axial excitation of a tightly focused radial vector beam. The electric field enhancement characteristic is quantified in relation with the groove number of grating, excitation wavelength, period of grating, and numerical aperture of the micro-objective (MO). These simulation results could be a good reference to fabricate a plasmonic tip for TERS applications, which is an effective way to promote the development of tip-enhanced near-field optical microscopy.

scholarly journals On the Large Near-Field Enhancement on Nanocolumnar Gold Substrates

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Pablo Díaz-Núñez ◽  
José Miguel García-Martín ◽  
María Ujué González ◽  
Raquel González-Arrabal ◽  
Antonio Rivera ◽  
...  
Keyword(s):  
Hot Spots ◽  
Near Field ◽  
Broad Band ◽  
Field Enhancement ◽  
Surface Enhanced Raman Spectroscopy ◽  
Plasmonic Nanostructures ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Nanostructured Gold ◽  
High Roughness

Abstract One of the most important and distinctive features of plasmonic nanostructures is their ability to confine large electromagnetic fields on nanometric volumes; i.e., the so-called hot spots. The generation, control and characterization of the hot spots are fundamental for several applications, like surface-enhanced spectroscopies. In this work, we characterize the near-field distribution and enhancement of nanostructured gold thin films fabricated by glancing angle deposition magnetron sputtering. These films are composed of columnar nanostructures with high roughness and high density of inter-columnar gaps, where the electromagnetic radiation can be confined, generating hot spots. As expected, the hot spots are localized in the gaps between adjacent nanocolumns and we use scattering-type scanning near-field optical microscopy to image their distribution over the surface of the samples. The experimental results are compared with finite-difference time-domain simulations, finding an excellent agreement between them. The spectral dependence of the field-enhancement is also studied with the simulations, together with surface-enhanced Raman spectroscopy at different excitation wavelengths in the visible-NIR range, proving a broad-band response of the substrates. These findings may result in interesting applications in the field of surface-enhanced optical spectroscopies or sensing.

scholarly journals Light-induced symmetry breaking for enhancing second-harmonic generation from an ultrathin plasmonic nanocavity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guang-Can Li ◽  
Dangyuan Lei ◽  
Meng Qiu ◽  
Wei Jin ◽  
Sheng Lan ◽  
...  
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Noble Metals ◽  
Second Harmonic ◽  
Near Field ◽  
Field Enhancement ◽  
Plasmonic Nanostructures ◽  
Far Field ◽  
Field Amplification ◽  
Gold Nanosphere

AbstractEfficient frequency up-conversion of coherent light at the nanoscale is highly demanded for a variety of modern photonic applications, but it remains challenging in nanophotonics. Surface second-order nonlinearity of noble metals can be significantly boosted up by plasmon-induced field enhancement, however the related far-field second-harmonic generation (SHG) may also be quenched in highly symmetric plasmonic nanostructures despite huge near-field amplification. Here, we demonstrate that the SHG from a single gold nanosphere is significantly enhanced when tightly coupled to a metal film, even in the absence of a plasmon resonance at the SH frequency. The light-induced electromagnetic asymmetry in the nanogap junction efficiently suppresses the cancelling of locally generated SHG fields and the SH emission is further amplified through preferential coupling to the bright, bonding dipolar resonance mode of the nanocavity. The far-field SHG conversion efficiency of up to $$3.56\times 10^{-7}$$ 3.56 × 1 0 − 7 W−1 is demonstrated from a single gold nanosphere of 100 nm diameter, two orders of magnitude higher than for complex double-resonant plasmonic nanostructures. Such highly efficient SHG from a metal nanocavity also constitutes an ultrasensitive nonlinear nanoprobe to map the distribution of longitudinal vectorial light fields in nanophotonic systems.

scholarly journals Optical Anapole Modes in Gallium Phosphide Nanodisk with Forked Slits for Electric Field Enhancement

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1490
Author(s):  
Jingwei Lv ◽  
He Zhang ◽  
Chao Liu ◽  
Zao Yi ◽  
Famei Wang ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Hot Spots ◽  
Gallium Phosphide ◽  
Physical Phenomenon ◽  
Near Field ◽  
Field Enhancement ◽  
High Refractive Index ◽  
Novel Approach ◽  
New Frontier

High refractive index dielectric nanostructures represent a new frontier in nanophotonics, and the unique semiconductor characteristics of dielectric systems make it possible to enhance electric fields by exploiting this fundamental physical phenomenon. In this work, the scattered radiation spectral features and field-enhanced interactions of gallium phosphide disks with forked slits at anapole modes are investigated systematically by numerical and multipole decomposition analyses. Additional enhancement of the electric field is achieved by opening the forked slits to create high-intensity hot spots inside the disk, and nearby molecules can access these hot spots directly. The results reveal a novel approach for near-field engineering such as electric field localization, nonlinear optics, and optical detection.

scholarly journals Large Near-Field Enhancement in Terahertz Antennas by Using Hyperbolic Metamaterials with Hole Arrays

2019 ◽  
Vol 9 (12) ◽  
pp. 2524 ◽  
Author(s):  
Cong Cheng ◽  
Wei Chen ◽  
Yuanfu Lu ◽  
Fangming Ruan ◽  
Guangyuan Li
Keyword(s):  
Electric Field ◽  
Field Component ◽  
Near Field ◽  
Field Enhancement ◽  
Dipole Antenna ◽  
Electric Field Component ◽  
Strong Light ◽  
Hyperbolic Metamaterials ◽  
Novel Approach ◽  
Hole Arrays

Terahertz antennas can greatly enhance the near fields and enable strong light–matter interactions, and thus have been widely used in applications such as terahertz sensing and detection. Here we propose a novel approach to further enhance the near fields in terahertz antennas. We show that by sandwiching hyperbolic metamaterials that are composed of InSb and SiO 2 multilayer and that are dressed with hole arrays, between a terahertz dipole antenna and the substrate, the near-field electric field intensities in the antenna can be further enhanced by more than three times. Simulations reveal that this enhancement originates from the doubly enhanced in-plane electric field component and the significantly enhanced out-of-plane electric field component. We expect this work will advance the design of terahertz antennas that are widely used in sensors and detectors.

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