Near- and mid-infrared bandgaps in a 1D photonic crystal containing superconductor and semiconductor-metamaterial

2019 ◽  
Vol 33 (20) ◽  
pp. 1950219 ◽  
Author(s):  
Chittaranjan Nayak ◽  
Alireza Aghajamali ◽  
Ardhendu Saha ◽  
Narottam Das
Keyword(s):  
Fill Factor ◽  
Transverse Electric ◽  
Incidence Angle ◽  
Blue Shift ◽  
Transverse Magnetic ◽  
Optical Devices ◽  
Multilayered Structure ◽  
Angle Of Incidence ◽  
Mid Infrared ◽  
Infrared Frequencies

By using the transfer matrix method, the theoretical investigation has been carried out in the near- and mid-infrared bandgaps for a periodic multilayered structure that was composed of superconductor (SC) and semiconductor-metamaterial. It was found that two bandgaps appeared within the computational regions which are effectively optimized by manipulating the thickness of the SC film, fill factor of the semiconductor-metamaterial and the incidence angle of the incident electromagnetic wave. However, the thickness of the SC film and fill factor of the semiconductor-metamaterial are responsible for the red-shift of bandgaps, while the blue-shift is accounted for by the angle of incidence for both transverse electric (TE) and transverse magnetic (TM) waves. It is notable, for the TM wave, that the bandgaps disappeared at the incident angles of approximately 60[Formula: see text]. Such properties are quite useful in designing any new types of edge filters and other optical devices in the near- and mid-infrared frequencies.

Magnetic plasmons induced in a dielectric-metal heterostructure by optical magnetism

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Shulei Li ◽  
Lidan Zhou ◽  
Mingcheng Panmai ◽  
Jin Xiang ◽  
Sheng Lan
Keyword(s):  
Transverse Electric ◽  
Incidence Angle ◽  
High Sensitivity ◽  
Critical Value ◽  
Transverse Magnetic ◽  
Quality Factors ◽  
Light Spectrum ◽  
Optical Resonances ◽  
Scattering Spectra ◽  
Plasmon Polaritons

Abstract We investigate numerically and experimentally the optical properties of the transverse electric (TE) waves supported by a dielectric-metal heterostructure. They are considered as the counterparts of the surface plasmon polaritons (i.e., the transverse magnetic (TM) waves) which have been extensively studied in the last several decades. We show that TE waves with resonant wavelengths in the visible light spectrum can be excited in a dielectric-metal heterostructure when the optical thickness of the dielectric layer exceeds a critical value. We reveal that the electric and magnetic field distributions for the TE waves are spatially separated, leading to higher quality factors or narrow linewidths as compared with the TM waves. We calculate the thickness, refractive index and incidence angle dispersion relations for the TE waves supported by a dielectric-metal heterostructure. In experiments, we observe optical resonances with linewidths as narrow as ∼10 nm in the reflection or scattering spectra of the TE waves excited in a Si3N4/Ag heterostructure. Finally, we demonstrate the applications of the lowest-order TE wave excited in a Si3N4/Ag heterostructure in optical display with good chromaticity and optical sensing with high sensitivity.

scholarly journals Graphene-based tunable hyperbolic microcavity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michał Dudek ◽  
Rafał Kowerdziej ◽  
Alessandro Pianelli ◽  
Janusz Parka
Keyword(s):  
Resonant Mode ◽  
Transverse Magnetic ◽  
Mid Infrared ◽  
Nanophotonic Devices ◽  
Wide Range ◽  
Fabry Perot ◽  
Hyperbolic Dispersion ◽  
Low Threshold ◽  
Infrared Frequencies ◽  
Infrared Wave

AbstractGraphene-based hyperbolic metamaterials provide a unique scaffold for designing nanophotonic devices with active functionalities. In this work, we have theoretically demonstrated that the characteristics of a polarization-dependent tunable hyperbolic microcavity in the mid-infrared frequencies could be realized by modulating the thickness of the dielectric layers, and thus breaking periodicity in a graphene-based hyperbolic metamaterial stack. Transmission of the tunable microcavity shows a Fabry–Perot resonant mode with a Q-factor > 20, and a sixfold local enhancement of electric field intensity. It was found that by varying the gating voltage of graphene from 2 to 8 V, the device could be self-regulated with respect to both the intensity (up to 30%) and spectrum (up to 2.1 µm). In addition, the switching of the device was considered over a wide range of incident angles for both the transverse electric and transverse magnetic modes. Finally, numerical analysis indicated that a topological transition between elliptic and type II hyperbolic dispersion could be actively switched. The proposed scheme represents a remarkably versatile platform for the mid-infrared wave manipulation and may find applications in many multi-functional architectures, including ultra-sensitive filters, low-threshold lasers, and photonic chips.

Study of the Absorptance of Si-gratings and of arrays of SiO2-filled trenches on Si-grating substrate

2016 ◽  
Vol 12 (2) ◽  
pp. 4278-4290
Author(s):  
Faouzi Ghmari ◽  
Ilhem Mezni
Keyword(s):  
Transverse Electric ◽  
Transverse Magnetic ◽  
Radiative Properties ◽  
Geometrical Parameters ◽  
Perfect Absorber ◽  
Angle Of Incidence ◽  
Patterned Wafers ◽  
Rigorous Coupled Wave Analysis ◽  
Rigorous Coupled Wave ◽  
Model Structures

The purpose of this paper is to study the radiative properties of two model structures. The first model (A-1) is a rectangular grating of silicon (Si). The second one (A-2) is obtained from A-1 by filling their trenches by SiO2. These patterned wafers are characterized by three geometrical parameters, the period d, the filling factorand the thickness h. To derive and compute the radiative properties we use a rigorous coupled wave analysis (RCWA) method. Our attention is focused on the absorptance of these structures when they are illuminated by a monochromatic plane wave. We investigate the effect of the filling factor on the absorptance versus the direction of the incident wave. At specific angles of incidence the effect of the period is also studied. Besides, the influence of the thickness h on the absorptance is included throughout this work. At the wavelength = 632,8nm, we especially show that we can identify several perfect absorber model structures characterized by specific parameters and by accurate angle of incidence. We show that this will be done in both transverse electric (TE) and transverse magnetic (TM) polarization cases.

scholarly journals Intensity Switchable and Wide-Angle Mid-Infrared Perfect Absorber with Lithography-Free Phase-Change Film of Ge2Sb2Te5

Micromachines ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 374
Author(s):  
Xiaomin Hua ◽  
Gaige Zheng
Keyword(s):  
Thin Film ◽  
Thin Layer ◽  
Crystalline State ◽  
Transverse Electric ◽  
Dynamic Control ◽  
Transverse Magnetic ◽  
Perfect Absorber ◽  
Wide Angle ◽  
Mid Infrared ◽  
Tunable Absorber

The range of fundamental phenomena and applications achievable by metamaterials (MMs) can be significantly extended by dynamic control over the optical response. A mid-infrared tunable absorber which consists of lithography-free planar multilayered dielectric stacks and germanium antimony tellurium alloy (Ge2Sb2Te5, GST) thin film was presented and studied. The absorption spectra under amorphous and crystalline phase conditions was evaluated by the transfer matrix method (TMM). It was shown that significant tuning of absorption can be achieved by switching the phase of thin layer of GST between amorphous and crystalline states. The near unity (>90%) absorption can be significant maintained by incidence angles up to 75 under crystalline state for both transverse electric (TE) and transverse magnetic (TM) polarizations. The proposed method enhances the functionality of MMs-based absorbers and has great potential for application to filters, emitters, and sensors.

scholarly journals Incidence Angle Effects on the Fabrication of Microstructures Using Six-Beam Laser Interference Lithography

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 62
Author(s):  
Tianxu Jia ◽  
Xiangxian Wang ◽  
Yaqian Ren ◽  
Yingwen Su ◽  
Liping Zhang ◽  
...  
Keyword(s):  
Incidence Angle ◽  
Low Cost ◽  
Transverse Magnetic ◽  
Interference Lithography ◽  
Angle Of Incidence ◽  
Laser Interference Lithography ◽  
Laser Interference ◽  
Beam Laser ◽  
Microstructure Fabrication ◽  
Mirror Group

This paper presents a theoretical demonstration of diverse microstructure fabrication by changing the angle of incidence of a six-beam laser interference lithography system. Different combinations are formed with transverse electric (TE) and transverse magnetic (TM) polarizations and various microstructures are simulated by controlling the high-reflectivity mirror group to adjust the incidence angle. This study indicates that the incidence angle has a considerable influence on the shape and period of the lattice, thereby contributing to the fabrication of microstructures with different arrangements. These structures include donut, circle, D-type, rectangular, triangular, U-type, and honeycomb lattices. The six-beam laser interference lithography technique is expected to benefit microstructure fabrication because of its simple operation, large writing area, and low cost, thereby promoting the development of micro-optics.

Design of Wavelength-Selective Surfaces for Mid-Infrared Detectors Using Heavily Doped Silicon Complex Gratings

2008 ◽  
Author(s):  
Y.-B. Chen ◽  
Z. M. Zhang
Keyword(s):  
Infrared Detectors ◽  
Transverse Magnetic ◽  
Radiative Properties ◽  
Angle Of Incidence ◽  
Mid Infrared ◽  
Infrared Wavelength ◽  
Thermal Radiative Properties ◽  
Heavily Doped ◽  
Plasmon Polaritons ◽  
Wave Incidence

The feasibility of using complex gratings for mid-infrared wavelength-selective absorbers is investigated. Nano/microscale surface features are employed for tailoring thermal radiative properties, which are much different from those of plain surfaces. High absorptance from heavily doped ( > 1×1020 cm−3) silicon for the transverse magnetic wave incidence can be achieved with one-dimensional periodic gratings by exciting surface plasmon polaritons. For simple binary gratings, the associated absorptance peak is narrowband and directional sensitive. These drawbacks can be remedied by using complex gratings, whose features are a superposition of multiple simple surface-relief gratings. The spectral absorptance displays a peak whose full-width-at-half-maximum (FWHM) exceeds 1.5 μm and is less sensitive to the angle of incidence. Moreover, the peak wavelength can be adjusted by varying the doping concentration and grating geometry. This study demonstrates that the use of complex gratings may significantly enhance the performance of infrared detectors.

Electron Channeling Patterns

1977 ◽  
Vol 35 ◽  
pp. 12-13
Author(s):  
David C. Joy
Keyword(s):  
Electron Diffraction ◽  
Incidence Angle ◽  
Photographic Plate ◽  
Diffraction Effect ◽  
Angle Of Incidence ◽  
Bulk Single Crystal ◽  
Time Resolved ◽  
Electron Channeling ◽  
Spatially Resolved ◽  
Large Bulk

Electron channeling patterns (ECP) were first found by Coates (1967) while observing a large bulk, single crystal of silicon in a scanning electron microscope. The geometric pattern visible was shown to be produced as a result of the changes in the angle of incidence, between the beam and the specimen surface normal, which occur when the sample is examined at low magnification (Booker, Shaw, Whelan and Hirsch 1967).A conventional electron diffraction pattern consists of an angularly resolved intensity distribution in space which may be directly viewed on a fluorescent screen or recorded on a photographic plate. An ECP, on the other hand, is produced as the result of changes in the signal collected by a suitable electron detector as the incidence angle is varied. If an integrating detector is used, or if the beam traverses the surface at a fixed angle, then no channeling contrast will be observed. The ECP is thus a time resolved electron diffraction effect. It can therefore be related to spatially resolved diffraction phenomena by an application of the concepts of reciprocity (Cowley 1969).

Single-peak-regulation and wide-angle dual-band metamaterial absorber based on hollow-cross and solid-cross resonators

2020 ◽  
Vol 91 (3) ◽  
pp. 30901
Author(s):  
Yibo Tang ◽  
Longhui He ◽  
Jianming Xu ◽  
Hailang He ◽  
Yuhan Li ◽  
...  
Keyword(s):  
Transverse Electric ◽  
Surface Current ◽  
Dielectric Substrate ◽  
Transverse Magnetic ◽  
Metamaterial Absorber ◽  
Absorption Peak ◽  
Dual Band ◽  
Single Peak ◽  
Wide Angle ◽  
Surface Current Density

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.

scholarly journals Fabrication-friendly polarization-sensitive plasmonic grating for optimal surface-enhanced Raman spectroscopy

2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Arpan Dutta ◽  
Tarmo Nuutinen ◽  
Khairul Alam ◽  
Antti Matikainen ◽  
Peng Li ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Fill Factor ◽  
Surface Enhanced Raman Spectroscopy ◽  
Transverse Magnetic ◽  
Raman Signal ◽  
Optical Resonance ◽  
Excitation Light ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Plasmonic Gratings

Abstract Plasmonic nanostructures are widely utilized in surface-enhanced Raman spectroscopy (SERS) from ultraviolet to near-infrared applications. Periodic nanoplasmonic systems such as plasmonic gratings are of great interest as SERS-active substrates due to their strong polarization dependence and ease of fabrication. In this work, we modelled a silver grating that manifests a subradiant plasmonic resonance as a dip in its reflectivity with significant near-field enhancement only for transverse-magnetic (TM) polarization of light. We investigated the role of its fill factor, commonly defined as a ratio between the width of the grating groove and the grating period, on the SERS enhancement. We designed multiple gratings having different fill factors using finite-difference time-domain (FDTD) simulations to incorporate different degrees of spectral detunings in their reflection dips from our Raman excitation (488 nm). Our numerical studies suggested that by tuning the spectral position of the optical resonance of the grating, via modifying their fill factor, we could optimize the achievable SERS enhancement. Moreover, by changing the polarization of the excitation light from transverse-magnetic to transverse-electric, we can disable the optical resonance of the gratings resulting in negligible SERS performance. To verify this, we fabricated and optically characterized the modelled gratings and ensured the presence of the desired detunings in their optical responses. Our Raman analysis on riboflavin confirmed that the higher overlap between the grating resonance and the intended Raman excitation yields stronger Raman enhancement only for TM polarized light. Our findings provide insight on the development of fabrication-friendly plasmonic gratings for optimal intensification of the Raman signal with an extra degree of control through the polarization of the excitation light. This feature enables studying Raman signal of exactly the same molecules with and without electromagnetic SERS enhancements, just by changing the polarization of the excitation, and thereby permits detailed studies on the selection rules and the chemical enhancements possibly involved in SERS.

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