Study of ultrafast resonant optical response toward thermal-free photonics

2015 Fiscal Year Final Research Report

• Project/Area Number: 24244048
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Condensed matter physics I
• Research Institution: Osaka Prefecture University
• Principal Investigator: Ishihara Hajime 大阪府立大学, 工学(系)研究科(研究院), 教授 (60273611)
• Co-Investigator(Kenkyū-buntansha): ASHIDA Masaaki 大阪大学, 基礎工学研究科, 教授 (60240818) ; ICHIMIYA Masayoshi 滋賀県立大学, 工学部, 准教授 (00397621) ; SHIM Yong-Gu 大阪府立大学, 工学研究科, 准教授 (20336803) ; YOKOSHI Nobuhiko 大阪府立大学, 工学研究科, 助教 (90409681)
• Project Period (FY): 2012-05-31 – 2016-03-31
• Keywords: 非線形光学 / 励起子 / CuCl / ZnO / 薄膜 / 四光波混合 / カー応答

Outline of Final Research Achievements

This study has successfully demonstrated a thermal-free ultrafast optical response for thin films in a crossover thickness regime between nano- and bulk regimes, where the excitonic mode with a wide radiative width exhibits a radiative decay faster than the dephasing at room temperature. We have observed an ultrafast response with 10 fs order by the excitation covering a whole width of the ultra-wide mode, where the signal reduction at room temperature is minimized. Our newly developed theory of nonlinear response of the ultra-wide modes well explains the above results. Furthermore, we have developed a theory for the ultrafast photoluminescence of confined excitons in the crossover thickness regime, and it proposes up-conversion photoluminescence from the superposed states of energetically different excitonic states coupled each other via radiation. We have also observed similar effects in experiments, which show the possibility for developing a new type of up-conversion light source.

Free Research Field

光物性理論