scholarly journals Near-Field Enhancement and Polarization Selection of a Nano-System for He-Ne Laser Application

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1421
Author(s):  
Wang ◽  
Chu ◽  
Yu ◽  
Gao ◽  
Peng

In this paper, we focus on transmission behavior based on the single aperture with a scatter. Both the near-field enhancement and polarization selection can be achieved numerically with a proposed nano-system under He-Ne laser wavelength. The nano-system consists of an Ag antenna, a wafer layer, an Ag film with an aperture and a dielectric substrate. Numerical results show that the near-field enhancement is related to the FP-like resonance base on surface plasmon polaritons (SPPs) in the metal–isolator–metal (MIM) waveguide for transverse magnetic (TM) polarization. The near-field optical spot is confined at the aperture export with a maximal electric intensity 20 times the value of the incident field for an antenna length of 430 nm. The transmission cutoff phenomenon for transverse electric (TE) polarization is because the transmission is forbidden for smaller aperture width. High extinction ratios of 9.6×10-8 (or 70.2 dB) and 4.4×10-8 (or 73.6 dB) with antenna lengths of 130 nm and 430 nm are achieved numerically with the nano-system. The polarization selective property has a good angular tolerance for oblique angles smaller than 15°. The spectral response is also investigated. We further demonstrate that the nano-system is applicable for another incident wavelength of 500 nm. Our investigation may be beneficial for the detection of polar molecules or local nano polarized nanosource.

electromagnetic field at the particl e has to be computed numerically. An example of such a computation using a program based on [49] is given in Fig. 4. But not only doe s the Mie theory describe an enhancement of the laser intensity in the particles' near field, it also predicts that for certain values of the size parameter nd/X (d denoting the particle diameter, À the laser wavelength) the enhancement should be particularly efficient, resulting in a resonant intensity enhancement, the so-called "Mie-resonances". 3.2.2. Near-field induced substrate damage When inspecting contaminated samples by scanning electron microscopy (SEM) or atomic force microscopy (AFM ) after DLC using ns laser pulses, the consequences of the field enhancement process became obvious: all over the cleaned areas w e found substrate damages localized exactly at the former particle positions [35, 37-39]. These damages manifested as melting pools or even holes in the surface, typical examples can be seen in Fig. 5. The consequences for the laser cleaning process are obvious. The intensity enhancement reduces the maximum laser fluence that can be applied in the process. Usually in laser cleaning studies [19, 31 ] the laser fluence corresponding to the melting threshold of a bare surface is taken as the damage threshold fluence. Our experiments show clearly that this is an inadequate definition. Instead one must take into account the enhanced laser fluence underneath the particles, as it will be discussed in Section 4. Fro m the obtained AFM images we were able to analyse in detail the surface profile at the damaged sites. Here we found that for high field enhancement factors the silicon substrate was not only molten , but that some material was even ablated (see Sec. 4). The momentum transfer to the particles during the ablation process significantly contributes to the cleanin g process and hence local substrate ablation

2003 ◽  
pp. 327-330

Author(s):  
Jian Wei You ◽  
Jie You ◽  
Martin Weismann ◽  
Nicolae C. Panoiu

Intriguing and unusual physical properties of graphene offer remarkable potential for advanced, photonics-related technological applications, particularly in the area of nonlinear optics at the deep-subwavelength scale. In this study, we use a recently developed numerical method to illustrate an efficient mechanism that can lead to orders of magnitude enhancement of the third-harmonic generation in graphene diffraction gratings. In particular, we demonstrate that by taking advantage of the geometry dependence of the resonance wavelength of localized surface-plasmon polaritons of graphene ribbons and discs one can engineer the spectral response of graphene gratings so that strong plasmonic resonances exist at both the fundamental frequency and third-harmonic (TH). As a result of this double-resonant mechanism for optical near-field enhancement, the intensity of the TH can be increased by more than six orders of magnitude. This article is part of the themed issue ‘New horizons for nanophotonics’.


2017 ◽  
Vol 5 (4) ◽  
Author(s):  
Anil Yuksel ◽  
Edward T. Yu ◽  
Jayathi Murthy ◽  
Michael Cullinan

Surface plasmon polaritons associated with light-nanoparticle interactions can result in dramatic enhancement of electromagnetic fields near and in the gaps between the particles, which can have a large effect on the sintering of these nanoparticles. For example, the plasmonic field enhancement within nanoparticle assemblies is affected by the particle size, spacing, interlayer distance, and light source properties. Computational analysis of plasmonic effects in three-dimensional (3D) nanoparticle packings are presented herein using 532 nm plane wave light. This analysis provides insight into the particle interactions both within and between adjacent layers for multilayer nanoparticle packings. Electric field enhancements up to 400-fold for transverse magnetic (TM) or X-polarized light and 26-fold for transverse electric (TE) or Y-polarized light are observed. It is observed that the thermo-optical properties of the nanoparticle packings change nonlinearly between 0 and 10 nm gap spacing due to the strong and nonlocal near-field interaction between the particles for TM polarized light, but this relationship is linear for TE polarized light. These studies help provide a foundation for understanding micro/nanoscale heating and heat transport for Cu nanoparticle packings under 532 nm light under different polarization for the photonic sintering of nanoparticle assemblies.


2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Bedir B. Yousif ◽  
Ahmed S. Samra

The optical properties of plasmonic nanoantennas are investigated in detail using the finite integration technique (FIT). The validity of this technique is verified by comparison to the exact solution generalized Mie method (GMM). The influence of the geometrical parameters (antenna length, gap dimension, and shapes) on the antenna field enhancement and spectral response is discussed. Localized surface plasmon resonances of Au (gold) dimers nanospheres, bowtie, and aperture bowtie nanoantennas are modeled. The enhanced field is equivalent to a strong light spot which can lead to the resolution improvement of the microscopy and optical lithography, thus increasing the optical data storage capacity. Furthermore, the sensitivity of the antennas to index changes of the environment and substrate is investigated in detail for biosensing applications. We confirm that our approach yields an exact correspondence with GMM theory for Au dimers nanospheres at gap dimensions 5 nm and 10 nm but gives an approximation error of less than 1.37% for gap dimensions 1 nm and 2 nm with diameters approaching 80 nm. In addition, the far-field characteristics of the aperture bowtie nanoantenna such as directivity and gain are studied. The promising results of this study may have useful potential applications in near-field sample detection, optical microscopy, and so forth.


Author(s):  
Alex J. Heltzel ◽  
Senthil Theppakuttai ◽  
John R. Howell ◽  
Shaochen Chen

An investigation on the features created on a silicon substrate by the irradiation of nanospheres on the substrate surface with a pulsed laser is presented. Silica nanospheres of diameter on the order of laser wavelength are deposited on silicon substrate and irradiated with a pulsed Nd: YAG laser. As a result, nanofeatures are created on the surface by the melting and resolidification of silicon. The experiment is repeated for different laser wavelengths (532 nm, and 355 nm), sphere diameters (640 nm, and 1.76 μm) and laser energies, and the effect of each of these parameters on the features created are studied. An analytical model based on Mie Theory complements the results. The model includes all evanescent terms and does not rely on either far field or size-parameter approximations. The predicted intensity distributions on the substrate indicate a strong near field enhancement confined to a very small area (nanometer scale). The results correlate well with the feature geometries obtained in the experiment.


Author(s):  
Anil Yuksel ◽  
Michael Cullinan ◽  
Jayathi Murthy

Surface plasmon polaritons are associated with the light-nanoparticle interaction and results in high enhancement in the gap between the particles. Indeed, this is affected by particle size, spacing, interlayer distance and light source properties. Polarization effect on three-dimensional (3D) and out of plane nanoparticle packings are presented herein to understand the out of plane configuration effect by using 532 nm plane wave light. This analysis gives insight on the particle interactions between the adjacent layers for multilayer nanoparticle packings. It has been seen that the electric field enhancement is up to 400 folds for TM (Transverse magnetic) or X-polarized light and 26 folds for TE (Transverse electric) or Y-polarized light. Thermo-optical properties change nonlinearly between 0 and 10 nm gap spacing due to the strong and non-local near-field interaction between the particles for the TM polarized light; however, this is linear for TE polarized light. This will give insight on the micro/nano heat transport for the interlayer particles for 100 nm diameter of Cu nanoparticle packings under 532 nm light under different polarization for 3-D interconnect (IC) manufacturing.


2018 ◽  
Vol 915 ◽  
pp. 28-33
Author(s):  
Aytac Onur ◽  
Mustafa Turkmen

In this study, a novel perfect absorber (PA) array based on H-shaped nanoapertures for bio-sensing applications in infrared regime is presented. Proposed PA array has a dual-band spectral response, and the locations of these resonances can be adjusted by varying the geometrical dimensions and layer thicknesses of the structure. Nearly unity absorbance is obtained from the PA array for both resonances. The structure design is based on the near field plasmon coupling between the gold film layer and the top nanoaperture array. In this context, the dielectric spacer layer is used to support this plasmon coupling and the gold film on the silicon substrate is also utilized to eliminate the transmittance through the structure. Different dielectric spacers (MgF2, SiO2, and Al2O3) are used to investigate the effects of dielectric spacer on the absorbance characteristics of proposed PA array. High field enhancement is achieved by the interaction of the sharp corners of nanoapertures. The near field enhancements are more than 1500 times at the first resonance frequency, more than 1000 times at the second resonance frequency which is highly desirable for the infrared bio-sensing applications. Due to the high near-field enhancement and nearly unity absorbance, the proposed dual-band PA array with adjustable spectral responses can be useful for bio-sensing applications in infrared regime.


2020 ◽  
Vol 91 (3) ◽  
pp. 30901
Author(s):  
Yibo Tang ◽  
Longhui He ◽  
Jianming Xu ◽  
Hailang He ◽  
Yuhan Li ◽  
...  

A dual-band microwave metamaterial absorber with single-peak regulation and wide-angle absorption has been proposed and illustrated. The designed metamaterial absorber is consisted of hollow-cross resonators, solid-cross resonators, dielectric substrate and metallic background plane. Strong absorption peak coefficients of 99.92% and 99.55% are achieved at 8.42 and 11.31 GHz, respectively, which is basically consistent with the experimental results. Surface current density and changing material properties are employed to illustrate the absorptive mechanism. More importantly, the proposed dual-band metamaterial absorber has the adjustable property of single absorption peak and could operate well at wide incidence angles for both transverse electric (TE) and transverse magnetic (TM) waves. Research results could provide and enrich instructive guidances for realizing a single-peak-regulation and wide-angle dual-band metamaterial absorber.


Nanophotonics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 2097-2105
Author(s):  
Xiaozhuo Qi ◽  
Tsz Wing Lo ◽  
Di Liu ◽  
Lantian Feng ◽  
Yang Chen ◽  
...  

AbstractPlasmonic nanocavities comprised of metal film-coupled nanoparticles have emerged as a versatile nanophotonic platform benefiting from their ultrasmall mode volume and large Purcell factors. In the weak-coupling regime, the particle-film gap thickness affects the photoluminescence (PL) of quantum emitters sandwiched therein. Here, we investigated the Purcell effect-enhanced PL of monolayer MoS2 inserted in the gap of a gold nanoparticle (AuNP)–alumina (Al2O3)–gold film (Au Film) structure. Under confocal illumination by a 532 nm CW laser, we observed a 7-fold PL peak intensity enhancement for the cavity-sandwiched MoS2 at an optimal Al2O3 thickness of 5 nm, corresponding to a local PL enhancement of ∼350 by normalizing the actual illumination area to the cavity’s effective near-field enhancement area. Full-wave simulations reveal a counterintuitive fact that radiation enhancement comes from the non-central area of the cavity rather than the cavity center. By scanning an electric dipole across the nanocavity, we obtained an average radiation enhancement factor of about 65 for an Al2O3 spacer thickness of 4 nm, agreeing well with the experimental thickness and indicating further PL enhancement optimization. Our results indicate the importance of configuration optimization, emitter location and excitation condition when using such plasmonic nanocavities to modulate the radiation properties of quantum emitters.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nantao Li ◽  
Taylor D. Canady ◽  
Qinglan Huang ◽  
Xing Wang ◽  
Glenn A. Fried ◽  
...  

AbstractInterferometric scattering microscopy is increasingly employed in biomedical research owing to its extraordinary capability of detecting nano-objects individually through their intrinsic elastic scattering. To significantly improve the signal-to-noise ratio without increasing illumination intensity, we developed photonic resonator interferometric scattering microscopy (PRISM) in which a dielectric photonic crystal (PC) resonator is utilized as the sample substrate. The scattered light is amplified by the PC through resonant near-field enhancement, which then interferes with the <1% transmitted light to create a large intensity contrast. Importantly, the scattered photons assume the wavevectors delineated by PC’s photonic band structure, resulting in the ability to utilize a non-immersion objective without significant loss at illumination density as low as 25 W cm−2. An analytical model of the scattering process is discussed, followed by demonstration of virus and protein detection. The results showcase the promise of nanophotonic surfaces in the development of resonance-enhanced interferometric microscopies.


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