Development of a frequency-dependent semi-implicit FDTD method and its application to the design of waveguide-based THz devices

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K04537
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21060:Electron device and electronic equipment-related
• Research Institution: Hosei University
• Principal Investigator: Shibayama Jun 法政大学, 理工学部, 教授 (40318605)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: FDTD法 / テラヘルツ波 / 表面プラズモンポラリトン / 表面プラズモン共鳴 / SPRセンサ

Outline of Final Research Achievements

The objective of this study is twofold. One is to develop a semi-implicit finite difference time domain (FDTD) method for the design of waveguide-type devices in the terahertz (THz) band with thin films of semiconductor InSb. The second is to analyze and design THz surface plasmon resonance (SPR) sensors and polarizers using the developed semi-implicit FDTD method.
Two and three-dimensional semi-implicit FDTD methods were developed. Compared to the conventional explicit FDTD method, the calculation time was reduced to roughly 30 and 20%, respectively, while maintaining the calculation accuracy.
In the design of polarizers, we proposed a new device that does not use interference of modes, but adds InSb layers on both sides of the core to attenuate and remove TE waves by plasmon excitation.

Free Research Field

機能素子工学

Academic Significance and Societal Importance of the Research Achievements

光波と電波の中間に存在するテラヘルツ(THz)波を用いた技術開発が進んでいる。本研究ではTHz波を利用した導波路デバイスの設計を効率よく行える半陰的FDTD法の開発と、開発したFDTD法を用いて種々のデバイスの設計を行った。計算時間を従来手法の20～30%にまで低減できたことから、極めて効率よいデバイス設計が可能になった。また、従来の干渉現象を用いた製造精度の要求される偏光子に対して、半導体層をコア両壁に設けた新たな偏光子を提案した。提案した偏光子では、特性が長さ方向に鈍感であり、高い製造精度がなくても良好な特性の得られる見込みが立った。