铂纳米材料的超快非线性及能量转移过程研究

项目名称： 铂纳米材料的超快非线性及能量转移过程研究

项目编号： No.61275117

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 无线电电子学、电信技术

项目作者： 高亚臣

作者单位： 黑龙江大学

项目金额： 76万元

中文摘要： 具有大的三阶极化率和超快响应的材料是高速全光开关、光学共轭、光计算中必需的材料。通常，材料在共振激发下会产生大的三阶非线性,但此时材料的线性吸收也很大，造成信号损失及温度升高，这对制作器件是很不利的。前期我们研究发现，在非共振时铂纳米粒子出现了大的饱和吸收，这是用以往的理论不能解释的现象。因此，本项目将利用飞秒OKE、Z-Scan、4f等技术研究铂纳米材料的超快非线性，揭示铂纳米粒子尺寸、形状、所处介质类型等对非线性强度的影响。利用飞秒时间分辩光谱技术测量光激发时铂纳米粒子的非线性建立及弛豫时间，进而揭示其中的能量转移、弛豫过程，阐明铂纳米粒子非共振饱和吸收产生的微观机理。利用高灵敏度泵浦-探测技术测量铂纳米粒子中的相干声子振荡模式、周期与调制情况，建立铂纳米粒子非共振激发能量转移过程描述模型。该研究将丰富人们对激光与材料作用的认识，为超快光学非线性材料的设计、合成提供理论依据。

中文关键词： 纳米材料；光学非线性；表面等离子体共振；能量转移；相干声子

英文摘要： Materials with large third-order optical nonlinearity and ultrafast response are indispensable.In general,under resonant exciting, materials can exhibit high third-order susceptibility.However,when excited at resonant frequence,material can also have large linear absorption which will lead to the loss of signal and increasing temperature.The effect is harmful for optoelectronic devices.Previously, we found that platinum nanoparticles can also show saturable absorption at non-resonant wavelength, which is not in agreement with the results obtained by other groups,and no resonable explanation were given.In our research now conducted in platinum, we will study why and how materials can show large third-order nonlinearity at non-resonant frequence. Firstly,ultrafast nonlinearity will be studied using OKE, Z-scan,4f technique,and the effect of size, shape, host matrix on nonlinearity of platinum nanoparticle will also be studied. Secondly,response time and energy relaxation processes will be investigated using femtosecond time-resolved pump-probe measurement.Furthermore a resonable explanation about saturable absorption at non-resonant wavelength will given.Finaly,mode,period and modulation of coherent phonons in platinum particles will be investigated.The research will help people know more about the interaction o

英文关键词： Nannomaterials；Optical nonlinearity；Surface plasmon resonance；Energy transport；Cohere phonon