Ultrafast radiative decay caused by coherent coupling between light and confined excitons in organic thin films

2014 Fiscal Year Final Research Report

• Project/Area Number: 24540321
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics I
• Research Institution: Osaka University
• Principal Investigator: ITOH Tadashi 大阪大学, ナノサイエンスデザイン教育研究センター, 特任教授 (60004503)
• Co-Investigator(Kenkyū-buntansha): ICHIMIYA Masayoshi 滋賀県立大学, 工学部, 准教授 (00397621) ; ASHIDA Masaaki 大阪大学, 大学院基礎工学研究科, 教授 (60240818)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: レーザー光物性 / 量子閉じ込め / 超高速輻射緩和 / サイズ共鳴増大 / 光学非線形性 / 四光波混合 / 分子性結晶 / 半導体単結晶薄膜

Outline of Final Research Achievements

We have investigated ultrafast radiative decay and optical nonlinearity caused by coherent coupling between light and confined exciton (so-called size-resonant enhancement) in organic thin films in comparison with those of inorganic thin films.
We have found the acceleration of radiative decay by one or two orders of magnitude (decay time of 250ps or less) of zero-phonon emission line of Frenkel exciton in 100nm-scale thick pure crystalline films of aromatic molecular anthracene. Judging from the high luminescence yield, we have concluded that the acceleration of the luminescence decay is probably caused by the size-resonant enhancement, although any characteristic structure caused by the exciton confinement is not yet found. In inorganic CuCl single-crystalline thin films, we have confirmed the effective enhancement of room-temperature optical nonlinearity of Wannier exciton caused by the size-resonant enhancement.

Free Research Field

無機・有機半導体ナノ構造物質のレーザー光物性実験