scholarly journals Study on Transmission Characteristics and Bandgap Types of Plasma Photonic Crystal

Photonics ◽  
2021 ◽  
Vol 8 (9) ◽  
pp. 401
Author(s):  
Yichao Liang ◽  
Zhen Liu ◽  
Jun Peng ◽  
Liguang Lin ◽  
Rubing Lin ◽  
...  

A plasma photonic crystal (PPC) was formed using an array of discharge plasma tubes. The transmission spectra and bandstructure of PPCs with different lattice types under different polarization modes were studied through simulation and measurement. To study the types of bandgap in PPCs, the bandstructure of the PPC is calculated using symplectic finite difference time domain (SFDTD), a modified plane wave expansion (PWE) method, and a finite element method (FEM) based on weak form equations. The bandstructure of the PPC is compared with the transmission curve results. The results show that the bandgap is stable in the PPC, and the experimental and numerical results of the transmission spectra agree well. There are different types of bandgap in the PPC; the bandgap under TE-like polarization is caused by localized surface plasmon (LSP) and Bragg scattering. The bandgap under TM-like polarization is caused by the cutoff effect of plasma on the electromagnetic wave and Bragg scattering. The lattice type also affects the position and number of the bandgap. The three methods have their advantages and disadvantages when calculating bandstructure. Therefore, it is necessary to combine the results of three methods and experimental results to accurately determine the bandgap type of the PPC.

Author(s):  
Y. N. Hua ◽  
G. B. Ang ◽  
S. Redkar ◽  
Yogaspari ◽  
Wilma Richter

Abstract In failure analysis of wafer fabrication, currently, three different types of chemical methods including 6:6:1 (Acetic Acid/HNO3/HF), NaOH and Choline are used in removing polysilicon (poly) layer and exposing the gate/tunnel oxide underneath. However, usage is limited due to their disadvantages. For example, 6:6:1 is a relatively fast etchant, but it is difficult to control the etch time and keep the oxide layer intact. Also, while using NaOH to remove poly and expose the silicon oxide, the solution needs to be heated. It is also difficult to etch a poly layer with a WSix or a CoSix silicide using NaOH. In this paper, we will discuss these 3 etchants in terms of their advantages and disadvantages. We will then introduce a new poly etchant, called HB91. HB91 is useful for removing poly to expose the gate/tunnel oxide for identification of related defects. HB91 is actually a mixture of two chemicals namely nitric acid (HNO3) and buffer oxide etchant (BOE) in a 9:1 ratio. The experimental results show that it is highly selective in poly removal with respect to the gate/tunnel oxide and is a suitable poly etchant especially for removing polysilicon with/without WSix and CoSix in the large capacitor structure. Application results of this poly etchant (HB91) will be presented.


2013 ◽  
Vol 479-480 ◽  
pp. 133-136
Author(s):  
Yih Bin Lin ◽  
Rei Shin Chen ◽  
Ting Chung Yu ◽  
Ju Feng Liu

A novel design of photonic crystal waveguide crossing with taper structure is proposed. Simulations are performed by finite-difference time-domain method. The results show the proposed design has both high transmission and low cross talk characteristics. The transmission band and low cross talk band can be tuned to match each other by adjusting the taper structure..


2013 ◽  
Vol 284-287 ◽  
pp. 2876-2879
Author(s):  
Yih Bin Lin ◽  
Jen Hao Cheng ◽  
Rei Shin Chen ◽  
Ting Chung Yu ◽  
Ju Feng Liu ◽  
...  

A novel design of photonic crystal waveguide crossing based on multimode-interference (MMI) structure is proposed. Two structures of difference device lengths are simulated and studied. The proposed structures have high transmission efficiency for a wide bandwidth. The crosstalk is -26dB with device length of 12 lattice periods and -39dB with device length of 24 lattice periods. The plane wave expansion method and finite-difference time-domain method are used to calculate the modal dispersion curve and field propagation, respectively. The proposed MMI-based waveguide crossing has the potential to be practical in high-density optical integrated circuits.


2021 ◽  
pp. 32-51
Author(s):  
Elena V. Generalova ◽  

The aim of the article is to review the ways of dictionary presentation of stable prepositional combinations and the factors essential for their lexical-grammatical status and the type of optimal lexicographic description. The object of the study is twocomponent prepositional combinations with stable meanings and the “preposition+noun” structure. The material of the article is data of different dictionaries of Russian presenting stable prepositional combinations. In the course of the study, the following questions were answered: why the definition and interpretation of the lexical-grammatical nature of stable prepositional combinations are so difficult and ambiguous; what lexicographic interpretation these units have in dictionaries of different types; what the advantages and disadvantages of different ways of dictionary interpretation of such language material are. The following methods were used: introspective (observation, generalization, classification), systematic lexicographic description according to dictionary parameters, dictionary definition analysis. The summary table of the lexicographic presentation of stable combinations allows seeing both the unresolved question of dictionary interpretation of such units and the patterns of their interpretation depending on the type of a dictionary. As a result of the analysis the following conclusions were drawn. 1) In modern Russian there is a rather large (about 2,000 units) class of language units (prepositional combinations), the lexical-grammatical status of which is not defined, and there is no term for their definition; this class is historically formed and continues to replenish. 2) The type of dictionary presentation of stable prepositional combinations is determined by the dictionary concept, grammatical and syntactic properties, presence of figurative meaning and possibility of component variation of such combinations. 3) The unresolved theoretical issues have as a result the lexicographic discrepancy in the presentation of these language units. Extreme lexicographic solutions are a separate dictionary entry for each combination and the presentation of such units only as stable combinations in the entry of a noun (presented in academic explanatory dictionaries). 4) Taking into account only the factor of presence/absence of a gap seems to formalize the dictionary presentation of adverbs with both conjoined and split spelling, really existing in Russian, and the position of recognition of these units with independent words and their isolate presentation is not impeccable for dictionary users. 5) In the author’s opinion, the presentation of stable prepositional combinations exclusively as independent vocabules is inferior to the traditional lexicographic approach because the isolated presentation of this material breaks the semantic connections of these complex lexical units; the most complex issue is the differentiation of adverbs with split spelling and stable combinations.


Studia BAS ◽  
2021 ◽  
Vol 1 (65) ◽  
pp. 147-169
Author(s):  
Katarzyna Wójtowicz

The aim of this paper is to explore the rationale for the reform of the shares of local government units (LGUs) in national income taxes in Poland as well as to evaluate the selected proposals for changes in this area. The paper begins by outlining the definition and the basic features of tax sharing in the context of fiscal federalism. The next section provides an overview of the tax shares operating in some OECD countries. The main part of the article focuses on the key principles of the tax sharing system in Poland. The author briefly examines the fiscal efficiency of this source of local revenue in different types of Polish LGUs and the most significant dysfunctions of Polish local tax shares. The final section investigates the most important proposals for the reform of tax sharing and discusses their advantages and disadvantages.


2011 ◽  
Vol 39 (10) ◽  
pp. 1969-1973 ◽  
Author(s):  
Chun-zao Li ◽  
Shao-bin Liu ◽  
Xiang-kun Kong ◽  
Hai-feng Zhang ◽  
Bo-rui Bian ◽  
...  

2011 ◽  
Vol 403-408 ◽  
pp. 1776-1780
Author(s):  
Yan Ma ◽  
Chun Lan Ma

This article focuses on FECs which is an error correction coding method and its applications in Internet and wireless communications. First, this article begins with the principles and the types of FECs. Then some typical applications n Internet and Wireless communications for each type of FECs are outlined. The next step is a comparison of the advantages and disadvantages between different types of FECs.


2018 ◽  
Vol 2018 (14) ◽  
pp. 669-672
Author(s):  
Qing Zhou ◽  
Shengpeng Yang ◽  
Changjian Tang ◽  
Yanyu Wei ◽  
Zhaoyun Duan ◽  
...  

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