Investigation on topological photonic effect by semiconductor nanocolumns

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K19059
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Applied condensed matter physics and related fields
• Research Institution: Sophia University
• Principal Investigator: Ema Kazuhiro 上智大学, 理工学部, 教授 (40194021)
• Project Period (FY): 2017-06-30 – 2020-03-31
• Keywords: フォトニック効果 / 窒化物半導体 / トポロジカルフォトニック / ナノコラム

Outline of Final Research Achievements

The purpose of this study is to experimentally confirm the optical version of the topological effect, "topological photonic effect", using semiconductor nanocolumns.
In the first half of the study, we investigated the effect of nanocolumn array fluctuations, and confirmed that when the fluctuations increased, the transition from photonic lasers to random lasers started. However, in the arrangement where the topological effect appears, there was no problem with some fluctuations, and it was proved that the topological protection is effective. In the latter half, we aimed at experiments of topological propagation, but due to the renovation of the laboratory, we could not obtain sufficient research results. Instead, we investigated the emission properties from localized states of InGaN nanocolumns in detail and laid the foundation for the topological laser.

Free Research Field

光物性，光エレクトロニクス

Academic Significance and Societal Importance of the Research Achievements

ユニークな光伝搬現象を示すトポロジカルフォトニック効果は新規な光デバイスとしての可能性が高い．本研究では，半導体ナノコラムでこれを実現させることを目指して，実際にデバイスを作製する際のゆらぎの効果について詳細に調べた．その結果，ゆらぎに対しては非常に強いというトポロジカル的保護が効いていることが確認できた．実験での実証に関しては大きな成果が得られなかったが，シミュレーションでもナノコラムが有効であることが示せたことは非常に価値がある．そのため，この研究は，より大きな研究プロジェクト（JST・CREST）に繋がっている．