近年來單分子螢光造影和分析已經躍升為解決生物系統中的動態與非均質性的利器。其中的非遷徙式單分子螢光能共振光譜造影方法，藉著把核酸固定在玻片上，大大簡化對於蛋白質與核酸的作用的造影與分析，使得像是蛋白質的構變化或在核酸上的遷移都可被即時觀察到。我們在此介紹分子螢光能共振的原理簡單的全反射式螢光顯微鏡的架設，和其成功地應用於解決核醣核酸聚合酶上核酸通道的案例。

In recent years， single moleucle optical imaging and analysis has emerged as a powerful way to unfold the dyanmic and heterogeneous behavior of numerous biological systems. Among all single moleucle technique， singlemolecule fluorescence resonance fluorescence energy transfer (smFRET) spectroscopic imaging in an immobilized fashion is particulary suitable for following the interactions between nucleic acids and proteins to 1 nm resolution with time resolution ranging from 10 ns to second. Here， we describe the principle of smFRET and a simple version of total internal reflection instrumentation and provide a successful application to the study of RNA exit channel on a transcribing RNA polymerase II.