Manifacturing room-temperature polariton devices based on organic microcavity

2020 Fiscal Year Final Research Report

• Project/Area Number: 18H01900
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 30020:Optical engineering and photon science-related
• Research Institution: Nara Institute of Science and Technology
• Principal Investigator: Katsuki Hiroyuki 奈良先端科学技術大学院大学, 先端科学技術研究科, 准教授 (10390642)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 励起子ポラリトン / 超高速分光 / 有機半導体 / ブロッホ表面波

Outline of Final Research Achievements

A polaritonic device composed of distributed Bragg reflector pair and thin layer of organic semiconductor is prepared, and its optical characteristics are studied. The formation of polariton condensate is detected with excitation fluence above the threshold. Femtosecond UV pump-white light probe spectroscopy is applied for the same sample under the polariton condensation. The relaxation dynamics of the exciton and polariton states are observed.
Another strong coupling system called Bloch surface wave polariton, composed of a single DBR mirror and thin layer of organic semiconductor, is studied numerically. The relation between the Rabi splitting parameter and the distribution of electric field around the mirror surface is discussed.
A UV pump-THz probe technique is applied for a sub-micron size crystal of MAPbBr3 perovskite, and it is concluded that the thermal excitation from the exciton state to the bottom of the conduction band is not efficient in this material.

Free Research Field

超高速分光

Academic Significance and Societal Importance of the Research Achievements

これまでの類似研究では、有機半導体の強結合ポラリトン状態でのポンププローブ実験は行われていたが、本研究では初めてポラリトン凝縮を実際に示す、閾値以上の励起光を入射した状態で、ポンププローブ分光を行うことができた。また、試料をより容易に作成でき、有限な面内運動量を持ったブロッホ表面波ポラリトン状態を保持するための設計指針について提案をすることができた。今後、有機半導体薄膜を利用したポラリトンデバイスを開発するにあたり、これらの結果は有用な情報である。