基于空气悬浮芯微结构光纤的高灵敏度荧光检测系统

High Sensitivity Fluorescence Detection System Based on Air Suspended Core Microstructural Fiber

当空心微结构光纤纤芯的尺寸和波长相近时,光在纤芯中的传输大大增强,并会在纤芯周围产生很强的倏逝场。报道了一种新型的纤芯直径仅为2μm的空气悬浮芯微结构光纤,该光纤通过薄片堆积法拉制而成,具有大倏逝场和微米级孔径的单元结构,在532nm波长处的损耗为0.16dB/cm,非常适合用于生化物质的传感探测。以该光纤作为传感探针,结合激光技术搭建了一套简易的荧光光谱探测系统,使用此系统对纳升量级的生物荧光标记材料CdTe/CdS/ZnS量子点进行荧光探测分析。利用该系统可探测荧光量子点的极限约为1nmol/L,相当于3.78×107个量子点,实现了高灵敏度、快速探测。基于空气悬浮芯微结构光纤的荧光检测系统为量子点标记的生物材料的灵敏检测提供了新的方法和思路。

When the core size of a holey microstructural fiber is close to the wavelength,the light propagation in the core is greatly enhanced and a strong evanescent field is produced around the core.A new air suspended core microstructural fiber with the core diameter of only 2μm is reported.The air suspended core fiber fabricated by sheet-stacking method has large evanescent field and the unit structure with micrometer-size holes.The air suspended core fiber,whose loss is 0.16 dB/cm at the wavelength of 532 nm,is very suitable for sensing detection of biochemical substances.Using the air suspended core fiber as sensing probe,we establish a simple fluorescence detection system combining with laser technology,and detect the fluorescence properties of bioluminescent labeling material CdTe/CdS/ZnS quantum dots with this system.The limit of the fluorescence quantum dots detected by this system is about 1 nmol/L（corresponds to 3.78×10^7 quantum dots）,which indicates that this system has the properties of high sensitivity and rapid detection speed.The fluorescence detection system based on the air suspended core microstructural fiber provides a new method and idea for the sensitive detection of biomaterials marked by quantum dots.