Ultrafast response of resonant third-order optical nonlinearity of organic J-aggregates

有机 J 聚集体共振三阶光学非线性的超快响应

基本信息

批准号：
15560033
负责人：
KASATANI Kazuo
金额：
$ 1.34万
依托单位：
Yamaguchi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

Although one-photon resonance enhances the third-order optical nonlinearity, their response could be very slow due to production of excited states. In addition, optical materials could be easily damaged.In the present study, thin films containing organic dyes, e.g., cyanine dyes, squarilium dyes, croconium dyes, naphthalocyanine dyes, and their J-like aggregates, showed high third-order optical nonlinearity and very fast response at the same time. The optical nonlinearity was measured using femtosecond degenerate four-wave mixing technique.First, we measured resonant molecular hyperpolarizabilities of dye monomers, and obtained values of 10^<-30> - 2 × 10^<-28> esu. These values contain only spontaneous electronic response and do not include slower responses such as population gratings. Then, we measured electronic values of third-order optical nonlinear susceptibility of polymer films, sol-gel silica films, and neat films including these dyes and aggregates.The thin films which gave J-like aggregates, electronic χ^<(3)>, and laser wavelength were as follows : Cyanine dye NK-2612 / PVA film (20 wt%) 1.1 × 10^<-7> esu (850 nm), cyanine dye DTDC / PMMA film (20wt%) 2.1 × 10^<-8> esu (850 nm), cyanine dye NK-3261 / neat film 1.1 × 10^<-7> esu (850 nm), cyanine dye NK-1969 / sol-gel silica film (30 wt%) 2 × 10^<-8> esu (850 nm), Silicon 2, 3-naphthalocyanine bis(trihexylsilyloxide) neat films 4 × 10^<-7> esu (800 nm). All J-aggregates we studied show very fast optical nonlinear response under resonant conditions.

虽然单光子共振增强了三阶光学非线性，但由于激发态的产生，它们的响应可能非常慢，此外，光学材料很容易被损坏。在本研究中，含有有机染料（例如花青）的薄膜。染料、squarilium染料、croconium染料、萘酞菁染料及其J类聚集体，同时表现出高三阶光学非线性和非常快的响应。使用飞秒简并四波混频技术测量非线性。首先，我们测量了染料单体的共振分子超极化率，并获得了 10^<-30> - 2 × 10^<-28> esu 的值。只包含自发电子响应，不包括布居光栅等较慢的响应。然后，我们测量了聚合物薄膜、溶胶凝胶二氧化硅薄膜的三阶光学非线性磁化率的电子值。产生J状聚集体、电子χ^<(3)>和激光波长的薄膜如下：花青染料NK-2612/PVA膜(20wt％) 1.1× 10^<-7> esu (850 nm)，花青染料 DTDC / PMMA 薄膜 (20wt%) 2.1 × 10^<-8> esu (850 nm)，花青染料 NK-3261 / 纯薄膜 1.1 × 10^<-7> esu (850 nm)，花青染料 NK-1969 / 溶胶-凝胶硅胶薄膜 (30 wt%) 2 × 10^<-8 > esu (850 nm)，硅 2, 3-萘酞菁双(三己基甲硅烷基氧化物) 纯薄膜4 × 10^<-7> esu (800 nm) 我们研究的所有 J 聚集体在谐振条件下都表现出非常快的光学非线性响应。