Highly sensitive time-resolved fluorescence measurements of ultra-thin films upon guided wave mode or surface plasmon resonance excitation and applications

我们已经在导波模式或表面等离子体共振激发下实现了对超薄膜的高灵敏时间分辨荧光测量，并将其应用于化学传感、分子光子学和对超薄聚合物薄膜中分子运动的非接触评估。主要成果如下：1.利用表面等离子体共振(SPR)或导波模式(GWM)中增强的消逝光作为激发光源，研制了一种新型的时间分辨荧光测量系统。用电场增强的逝去光激发不同染料掺杂的脱氧核糖核酸和疏水脱氧核糖核酸薄膜在银膜上旋涂，获得了ppm到亚ppm量级的氧化亚氮。3.光通信波长…的超快和大吸收变化通过对具有光致电子转移和氧化还原活性离子对之间反向反应的π电子系统进行瞬时扩展，在固体薄膜中获得了更大的GTH区域。这种聚合物薄膜可用于电信系统中的太赫兹全光信息处理。4.用GWM或SPR激发研究了分散在聚乙烯醇或聚三环十二烷超薄膜中的染料的荧光寿命。基于低折射率聚合物和光响应性聚合物组成的复合GWM几何结构的光致复折射率变化，提出了一种高灵敏度的超快全光光调制方法。与简单的透射型器件或金属薄膜中的GWM几何结构相比，本器件可以给出高度增强的探测光变化。在这种几何结构中使用了光电变色聚合物(如上图3所示)来演示对飞秒激光激发的超快反射控制。较少

We have achieved highly sensitive time-resolved fluorescence measurements of ultra-thin films upon guided wave mode or surface plasmon resonance excitation and their applications to chemical sensing, molecular photonics and non-contact evaluation of molecular motion in very thin polymer films. Major achievements are as follows :1.A novel time-resolved fluorescence measurement system was developed by using enhanced evanescent light at surface plasmon resonance (SPR) or guided wave mode (GWM) as an excitation light source.2.We demonstrated that highly sensitive, fast responsive and highly reversible sensing of nitrogen dioxide, nitric oxide, and nitrous oxide at a ppm-to-sub-ppm level has been achieved by fluorescence measurements upon excitation of various dye-doped deoxyribonucleic acid (DNA) and hydrophobic DNA thin films spin-coated on a thin silver film by electric field enhanced evanescent light at SPR.3.Ultrafast and large absorption change in the optical telecommunication wavelen … More gth region was achieved in solid films by making transitory expansion of a π-electronic system with photoinduced electron transfer and reverse reactions between redox-active ion pairs. This polymer film may be applied to terahertz all optical information processing in the telecommunication system.4.Fluorescence lifetimes of dyes dispersed in ultrathin films of poly(vinyl alcohol) or polytricyclodecane were examined by GWM or SPR excitation. The fluorescent behavior of the dyes at interface or surface of ultrathin films was strongly suggested to be different from that in the bulk state.5.Highly sensitive ultrafast all-optical light modulation was proposed on the basis of photoinduced complex refractive-index changes in composite GWM geometry composed of a low-refractive-index polymer and a photoresponsive polymer. The present device can give highly enhanced changes of probe light as compared with simple transmission-type devices or the GWM geometry in a metal thin film. A photoelectrochromic polymer (shown above 3) was employed in this geometry to demonstrate ultrafast reflectance control upon femtosecond laser excitation. Less