Numerical investigation of a narrowband absorber with a simple structure

Ninawe, Akanksha; Dhawan, Anuj; Xu, Xianfan

doi:10.1364/osac.412046

Cited by 9 publications

(3 citation statements)

References 37 publications

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“…The black curve shows a possible convolution (close to the experimental system) of ΔT spectra from the different lattice periodicities. We note that the different plasmonic modes (particularly the broad resonance noted at ∼700 nm) of the system changes with increase in lattice periodicity in a redshifted manner as noted previously [86][87][88]. Further, for Λ>530 nm, additional sharp plasmon peaks occur in the lower wavelength range which could be the result of a strong coupling mechanism between the higher order multipoles excited in the tightly confined particles which takes precedence over the lattice periodicity modes as Λ increases.…”

Section: Resultssupporting

confidence: 71%

Chiro-optical response of a wafer scale metamaterial with ellipsoidal metal nanoparticles

et al. 2021

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We report a large chiro-optical response from a nanostructured film of aperiodic dielectric helices decorated with ellipsoidal metal nanoparticles. The influence of the inherent fabrication variation on the chiro-optical response of the wafer-scalable nanostructured film is investigated using a computational model which closely mimics the material system. From the computational approach, we found that the chiro-optical signal is strongly dependent on the ellipticities of the metal nanoparticles and the developed computational model can account for all the variations caused by the fabrication process. We report the experimentally realized dissymmetry factor ∼1.6, which is the largest reported for wafer scalable chiro-plasmonic samples till now. The calculations incorporate strong multipolar contributions of the plasmonic interactions to the chiro-optical response from the tightly confined ellipsoidal nanoparticles, improving upon the previous studies carried in the coupled dipole approximation regime. Our analyzes confirm the large chiro-optical response in these films developed by a scalable and simple fabrication technique, indicating their applicability pertaining to manipulation of optical polarization, enantiomer selective identification and enhanced sensing and detection of chiral molecules.

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Section: Resultssupporting

confidence: 71%

Chiro-optical response of a wafer scale metamaterial with ellipsoidal metal nanoparticles

et al. 2021

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“…Plasmonics is an intriguing field of research in photonics which involves manipulation of light at the nano-scale as well as enhanced light-matter interactions, with multitude of applications in plasmonic semiconductors [1][2][3][4], nonlinear plasmonics [5,6], near-field optical imaging [7][8][9], chiral plasmonics [10][11][12][13][14], plasmonic solar cells [15][16][17], topological insulator based optoelectronic devices [18,19], metamaterial absorbers [20][21][22],…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of plasmonic bowtie nanorings with embedded nanoantennas for achieving high SEIRA enhancement factors

Ninawe

Dhawan

2022

Mater. Res. Express

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This paper presents the numerical investigation of several complex plasmonic nanostructures — bowtie nanoring and crossed-bowtie nanoring nanoantennas with embedded bowtie nanoantennas and crossed-bowtie nanoantennas — for surface enhanced infrared absorption (SEIRA) spectroscopy-based substrates. The proposed nanostructures exhibit substantially large SEIRA enhancement-factor (~ 8.1 × 105) compared to previously reported enhancement factor values for bowtie nanoantennas or nanoring antennas. The plasmonic properties of the proposed nanostructures have been studied by the numerical evaluation of the near-field electromagnetic enhancement at resonant plasmon mode excitation wavelengths in the mid-IR spectral regime. The highest SEIRA enhancement of ~ 8.1 × 105 occurs at a wavelength of ~ 6800 nm (6.8 μm). A substantial electric field enhancement as large as ~ 375, corresponding to SEIRA EF of ~ 1.4 × 105 is noted even when the minimum gaps between the plasmonic nanostructures is as large as 10 nm, which can easily be fabricated using the conventional nanolithography techniques. The occurrence of several electric field hotspots due to the presence of plasmonic nanoantennas embedded inside the nanorings was observed, as the electric fields are enhanced in the vicinity of the plasmonic nanostructures being proposed. The multiple electric field hotspots in the proposed nanostructures can lead to larger average electric field enhancement as well as the average SEIRA enhancement for these substrates. Moreover, by embedding plasmonic nanoantenna structures inside the bowtie nanorings and crossed-bowtie nanorings, large spectral tunability of plasmon resonance wavelengths is achieved in the spectral regime from 4 μm to 8 μm. This is done by varying a larger number of spectral parameters that are present in these complex nanostructures. This paper also reports a novel configuration of crossed-bowtie nanoring plasmonic structure exhibiting less polarization dependence of the SEIRA enhancement-factor. The proposed structures in this paper can be fabricated by the state-of-the-art nanofabrication technologies.

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“…Since Landy et al firstly reported the concept of the perfect MMA consisting of two resonators coupled to the electric and magnetic fields separately to absorb the incident waves [7], the realizations of the high performance and multi-functional MMAs for various applications are always the important goals pursued by researchers [8,9]. Up to now, various MMAs, which are either multiple bands [10][11][12], polarization-insensitive [13,14] or polarization-sensitive [15,16], ultra-narrowband [17][18][19][20], and broadband [21], have been successfully realized to absorb EM waves across the whole spectrum from microwave to terahertz [22][23][24][25]. Chen proposed the interference theory to explain the physical mechanism of MMAs, an extremely broadband absorber based on destructive interference mechanism was demonstrated [26].…”

Section: Introductionmentioning

confidence: 99%

Circular dichroism assisted bi-directional absorbers

Yang¹,

Li²,

Wang³

et al. 2021

J. Phys. D: Appl. Phys.

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Chirality, a geometric property that is of great importance in chemistry, biology, and medicine, has spurred many breakthroughs in the field of multi-dimensional metasurfaces that provide efficient ways of flexibly manipulating amplitude and phase of circular polarization (CP) waves. As one of the most important applications, chiral metamaterials can be used to implement novel absorbers. Herein, an ultra-thin wideband circular dichroic asymmetric metasurface was implemented via loading resistive film into chiral resonators. Opposite and reversible polarization conversion and circular dichroism (CD) were realized as being illuminated by CP waves from both sides meanwhile. Theoretical derivation and simulation verify that the polarization conversion and CD enhancement utilizing multi-layer CD metasurface. It is also found that the orientation angle of the meta-atom of each layer plays an important role in the CD enhancement, which paves a new way for CD enhancement. In addition, the coupling between the CD resonators was utilized to manipulate CD. On this basis, an ultra-thin polarization-insensitive absorber was achieved by employing a C4 2×2 CD resonator array, which was identical illuminating from front and back sides. Circular dichroic absorbers possess great potential in practical applications, ranging from stealth technology, antenna isolation, multi-functional microwave devices, chiral sensing, and catalysis.

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Numerical investigation of a narrowband absorber with a simple structure

Cited by 9 publications

References 37 publications

Chiro-optical response of a wafer scale metamaterial with ellipsoidal metal nanoparticles

Chiro-optical response of a wafer scale metamaterial with ellipsoidal metal nanoparticles

Numerical investigation of plasmonic bowtie nanorings with embedded nanoantennas for achieving high SEIRA enhancement factors

Circular dichroism assisted bi-directional absorbers

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