Scanning near-field optical microscopy and spectroscopy studies of quantum dots.

对生物系统和过程的研究仅限于衍射光学显微镜。扫描近场光学显微镜（SNOM）是一种克服衍射极限，利用光分辨纳米尺度特征的技术。然而，该技术的固有性质导致它在基于标准有机染料的荧光研究时受到低光强度的限制。本提案试图通过考虑非有机量子点来克服这个问题。这些染料目前正在医学上进行探索，因为它们比普通的有机染料产生更强烈、更可靠的荧光发射源。量子点也有能力通过改变其大小来调整发射不同波长的光，因此可以给出特定的光谱特征。该提案旨在将量子点（由CdSe/ZnS制成）固定在电子束电阻中，然后用扫描近场显微镜探测它们。荧光特征将通过SNOM仪器的发展进行分析，这将使其能够从光谱上确定量子点荧光发射的性质。通过电子束抗蚀膜内量子点的精心制备，可以获得单个量子点的光谱特征。这个项目是将量子点引入生物系统的一个跳板，在生物系统中，量子点可以与近场显微镜一起使用，产生具有纳米级分辨率和光谱灵敏度的增强图像。

The study of biological systems and processes is limited in optical microscopy by diffraction. Scanning near-field optical microscopy (SNOM) is a technique which can overcome the diffraction limit and resolve nanoscale features with light. However the intrinsic nature of the technique results in it being limited by low light intensities when based on fluorescence studies of standard organic dyes. This proposal seeks to overcome this problem by considering in-organic quantum dots. These are currently being explored in medicine because they produce a far more intense and reliable source of fluorescent emission than normal organic dyes. Quantum dots also have the ability to be tuned to emit at different wavelengths just by changing their size and hence can give specific spectral characteristics. The proposal aims to immobilise the quantum dots (made from CdSe/ZnS) in an e-beam resist and then probe them with the scanning near-field microscope. The fluorescent signature will then be analysed via developments to the SNOM instrument that will enable it to spectrally determine the nature of the fluorescent emission from the quantum dot. Via the careful preparation of the quantum dots within the e-beam resist film, spectral signatures from single quantum dots will be achieved. This project represents a stepping stone to the potential introduction of quantum dots into a biological system where they can be used together with the near-field microscope to produce enhanced images with nanoscale resolution and spectral sensitivity.