Generation of Entangled Photon Pairs from a Semiconductor slab: A Theoretical Study on Optimal Slab Width and Microcavity Effects

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K03705
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
• Research Institution: Tokyo Denki University
• Principal Investigator: Ajiki Hiroshi 東京電機大学, 理工学部, 教授 (60283735)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: 量子もつれ光子対 / 励起子分子 / 表面励起子ポラリトン / 薄膜 / ドレスト状態 / 励起子

Outline of Final Research Achievements

We theoretically investigate the generation of quantum entangled photon pairs from a biexciton in a slab embedded in a microcavity. In the strong coupling regime, the intermediate states in the generation process are exciton-photon coupled states called two-excited dressed states. We have calculated the transition probability from the biexciton to the two-excited dressed state under various parameters and investigated the conditions under which the transition probability becomes high.
When a biexciton radiatively decays to a surface polariton, it is difficult to extract an entangled photon pair. Therefore, we have investigated the surface polariton in the presence of a cavity. It is found that the transition to the surface polariton is strongly suppressed in a high-Q cavity.

Free Research Field

光物性理論

Academic Significance and Societal Importance of the Research Achievements

量子情報処理技術の実用化に向けて様々な量子もつれ状態が提案されているが，量子もつれ光子対は環境からの影響が極めて小さい点に長所がある．もつれ光子対の実験の多くは量子ドットを利用しているが，光と物質系の相互作用が強くなる薄膜，さらにはこれを共振器に埋め込んだ系により，効率よくもつれ光子対を生成できると考えられる．本研究では，共振器-薄膜系に特有なドレスト状態を経て励起子分子から量子もつれ光子対が生成される過程を理論的に考察し，量子もつれ光子対の生成に不利な表面ポラリトンへの遷移が，共振器により強く抑制されることを明らかにした点で意義がある.