scholarly journals Electromagnetic controllable surfaces based on trapped-mode effect

2012 ◽  
Vol 1 (2) ◽  
pp. 89 ◽  
Author(s):  
V. Dmitriev ◽  
S. Prosvirnin ◽  
V. R. Tuz ◽  
M. N. Kawakatsu
Keyword(s):  
Active Material ◽  
Optical Excitation ◽  
Optically Active ◽  
Periodic Cell ◽  
Trapped Mode ◽  
Periodic Arrays ◽  
External Static Magnetic Field ◽  
Metallic Inclusions ◽  
Theoretical Investigations ◽  
Mode Effect

In this paper we present some recent results of our theoretical investigations of electromagnetically controllable surfaces. These surfaces are designed on the basis of periodic arrays made of metallic inclusions of special form which are placed on a thin substrate of active material (magnetized ferrite or optically active semiconductor). The main peculiarity of the studied structures is their capability to support the trapped-mode resonance which is a result of the antiphase current oscillations in the elements of a periodic cell. Several effects, namely: tuning the position of passband and the linear and nonlinear (bistable) transmission switching are considered when an external static magnetic field or optical excitation are applied. Our numerical calculations are fulfilled in both microwave and optical regions.

Recent Aspects on the Effect of Inclusion Characteristics on the Intragranular Ferrite Formation in Low Alloy Steels: A Review

2017 ◽  
Vol 36 (4) ◽  
pp. 309-325 ◽  
Author(s):  
Wangzhong Mu ◽  
Pär Göran Jönsson ◽  
Keiji Nakajima
Keyword(s):  
Heat Affected Zone ◽  
Low Alloy Steels ◽  
Low Carbon ◽  
Intragranular Ferrite ◽  
Metallic Inclusions ◽  
Theoretical Investigations ◽  
Alloy Steels ◽  
Institute Of Technology ◽  
Future Work

AbstractIntragranular ferrite (IGF), which nucleates from specific inclusion surfaces in low alloy steels, is the desired microstructure to improve mechanical properties of steel such as the toughness. This microstructure is especially important in the coarse grain heat affected zone (CGHAZ) of weldments. The latest review paper focusing on the role of non-metallic inclusions in the IGF formation in steels has been reported by Sarma et al. in 2009 (ISIJ int., 49(2009), 1063–1074). In recent years, large amount of papers have been presented to investigate different issues of this topic. This paper mainly highlights the frontiers of experimental and theoretical investigations on the effects of inclusion characteristics, such as the composition, size distribution and number density, on the IGF formation in low carbon low-alloyed steels, undertaken by the group of Applied Process Metallurgy, KTH Royal Institute of Technology. Related results reported in previous studies are also introduced. Also, plausible future work regarding various items of IGF formation is mentioned in each section. This work aims to give a better control of improving the steel quality during casting and in the heat affected zone (HAZ) of weldment, according to the concept of oxide metallurgy.

Plasmonic Biofoam: A Versatile Optically Active Material

Nano Letters ◽  
2015 ◽  
Vol 16 (1) ◽  
pp. 609-616 ◽  
Author(s):  
Limei Tian ◽  
Jingyi Luan ◽  
Keng-Ku Liu ◽  
Qisheng Jiang ◽  
Sirimuvva Tadepalli ◽  
...  
Keyword(s):  
Active Material ◽  
Optically Active ◽  
Optically Active Material

Critical Pitch in Thin Cholesteric Films with Homeotropic Boundaries

1976 ◽  
Vol 31 (1) ◽  
pp. 41-46 ◽  
Author(s):  
Fred Fischer
Keyword(s):  
General Solution ◽  
Active Material ◽  
Film Plane ◽  
Optically Active ◽  
Critical Voltage ◽  
Director Field ◽  
Planar Texture ◽  
Normal Orientation ◽  
Additional Influence ◽  
Optically Active Material

Calculations of the planar cholesteric texture with homeotropic boundary conditions are presented. At a constant film thickness there is a critical twist t0c below which the planar texture has transformed into a homeotropic one. The additional influence of an external field is discussed for positive and negative anisotropy and with field orientations parallel or normal to the film plane. A general solution of the director field has been found for a normal orientation of the field. A properly adjusted twist t0 obtained by dilution of an optically active material in a nematic matrix opens a possibility to reduce the critical voltage in technical devices.

scholarly journals Nanoscale Plasmonic Devices Based on Metal-Dielectric-Metal Stub Resonators

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Yin Huang ◽  
Changjun Min ◽  
Liu Yang ◽  
Georgios Veronis
Keyword(s):  
Transmission Lines ◽  
Slow Light ◽  
Electromagnetically Induced Transparency ◽  
Active Material ◽  
Plasmonic Waveguide ◽  
Plasmonic Waveguides ◽  
Periodic Arrays ◽  
Research Activities ◽  
Induced Transparency

We review some of the recent research activities on plasmonic devices based on metal-dielectric-metal (MDM) stub resonators for manipulating light at the nanoscale. We first introduce slow-light subwavelength plasmonic waveguides based on plasmonic analogues of periodically loaded transmission lines and electromagnetically induced transparency. In both cases, the structures consist of a MDM waveguide side-coupled to periodic arrays of MDM stub resonators. We then introduce absorption switches consisting of a MDM plasmonic waveguide side-coupled to a MDM stub resonator filled with an active material.

RESONANT LIGHT SCATTERING AND HIGHER HARMONIC GENERATION BY PERIODIC SUBWAVELENGTH ARRAYS

2009 ◽  
Vol 23 (27) ◽  
pp. 5191-5236 ◽  
Author(s):  
SERGEI V. SHABANOV
Keyword(s):  
Harmonic Generation ◽  
Bound States ◽  
Nonlinear Optical ◽  
Trapped Modes ◽  
Trapped Mode ◽  
Periodic Arrays ◽  
Optical Effects ◽  
Nonlinear Optical Effects ◽  
Higher Harmonic Generation ◽  
Higher Harmonic

Scattering of light on periodic subwavelength arrays is studied in the framework of the resonant scattering theory. With various examples of periodic structures it is demonstrated that: (i) an enhanced reflectance or transmittance is associated with the existence of trapped modes (quasi-stationary modes of light confined in the vicinity of the scattering structure); (ii) scattering structures may have trapped modes due to peculiarities their geometry (geometrical modes) and the dispersive properties of their material (material modes); a practical criterion based on the scaling symmetry of Maxwell's equations is proposed to distinguish them; (iii) the trapped mode field can be significantly amplified, as compared to the incident wave amplitude, in some regions of the structure; (iv) the amplification increases with increasing the lifetime of the trapped mode; (v) this effect can be used to enhance nonlinear optical effects (a resonant higher harmonic generation is studied in detail as an example). The theory of coupled resonances is developed and used to prove that there exist bound states of light in the radiation continuum (resonances with the vanishing width) in periodic arrays. The bound states are neither modes in metal cavities nor modes in photonic crystal defects. Structures supporting the bound states of light can be used to enhance and control nonlinear optical effects in subwavelength periodic arrays.

Sign in / Sign up

Export Citation Format

Share Document