提高液体中AFM微悬臂梁品质因数的研究

提出了一种能够把在液体环境中工作的原子力显微镜(Atomic Force Microscoy)的微悬臂梁的低品质因数提高二个数量级的方法,这是通过一个正反馈环路实现的，同时采用一个锁相环(Phase Lock Loop)来监控微悬臂梁谐振频率并产生一个驱动信号使用可变移相器和可变增益放大器对微悬臂梁振荡信号进行调节，调节后的信号也加入到驱动信号中，从而提高了原子力显微镜的动态力灵敏度和分辨力。

Amplifying of the quality factor of AFM microcantilevers in liquid environment

In this article, a new technique is presented. The technique increases the low quality factor of microcantilevers of an Atomic Force Microscopy (AFM) in liquid environment up to three orders of magnitude. This is achieved via a positive feedback loop. At the same time a Phase Lock Loop(PLL) to track the resonance frequency of the microcantilever is applied, the PLL produces a driving signal. A variable phase shifter and a variable gain amplifier are used to process the microcantilever oscillation signal, the processed signal is added to the driving dignal. Therefore the dynamic force sensitivity and the resolution of a conventional AFM are improved.