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.

尽管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，光学材料很容易受到损害。在本研究中，含有有机染料的薄膜，例如氰氨基染料，苏猴染料，鳄鱼染料，萘丙氨酸染料及其J样聚集体，显示出高三阶光学非线性和非常快速的响应。使用飞秒脱位四波混合技术测量光学非线性。首先，我们测量了染料单体的谐振分子超极化能力，并获得了10^<-30> -2×10×10^<-28> ESU的值。这些值仅包含赞助电子响应，并且不包括较慢的响应，例如人口光栅。然后，我们测量了聚合物薄膜，溶胶 - 凝胶二氧化硅膜和包括这些染料和聚集体在内的整齐膜的三阶光学非线性敏感性的电子价值。薄膜给出了类似J的聚集体，电子χ^<（3）>和激光波长，如下所示：cananine dye nk-2612 / pva（20 w filments filments：20 wte <20 wt f a> 20 w。 esu (850 nm), cyanine dye DTDC / PMMA film (20 wt%) 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），硅2，3-萘丙氨酸双Bis（Trihexylsilyloxide）纯净膜4×10^<-7> ESU（800 nm）。我们研究的所有J种群在谐振条件下显示出非常快速的光学非线性响应。