A new detection system for extremely small vertically mounted cantilevers
A new detection system for extremely small vertically mounted cantilevers
复制标题
DOI：
10.1088/0957-4484/19/38/384002
复制
发表时间：
2008-09-24
期刊：
影响因子：
3.5
通讯作者：
Miles, M. J.
中科院分区：
文献类型：
--
作者：
Antognozzi, M.;Ulcinas, A.;Miles, M. J.
目前在扫描力显微镜中使用的检测技术限制了探针的几何尺寸，从而限制了它们的力灵敏度和时间响应。提出了一种基于散射消逝电磁波(SEW)的垂直安装悬臂梁端部位移检测新技术。用不同的悬臂梁尺寸测试了该方法的分辨率，并建立了最大化检测灵敏度的理论模型。这里介绍的应用清楚地表明，SEW检测系统能够使用亚微米尺寸的力传感器，为生物分子系统的研究和高速成像打开了新的可能性。成功地测试了两种类型的悬臂梁：一种是弹簧常数为0.17pN nm(-1)、共振频率为32 kHz的高力敏感杠杆；另一种是弹性常数为50pN nm(-1)、共振频率为1.8 MHz的高速杠杆。这两种力传感器都是通过在聚焦离子束系统中对商用微悬臂梁进行改造来制造的。需要强调的是，这些改装的悬臂梁不能用商用原子力显微镜中使用的传统光学检测系统进行检测。
Detection techniques currently used in scanning force microscopy impose limitations on the geometrical dimensions of the probes and, as a consequence, on their force sensitivity and temporal response. A new technique, based on scattered evanescent electromagnetic waves ( SEW), is presented here that can detect the displacement of the extreme end of a vertically mounted cantilever. The resolution of this method is tested using different cantilever sizes and a theoretical model is developed to maximize the detection sensitivity. The applications presented here clearly show that the SEW detection system enables the use of force sensors with sub-micron size, opening new possibilities in the investigation of biomolecular systems and high speed imaging. Two types of cantilevers were successfully tested: a high force sensitivity lever with a spring constant of 0.17 pN nm(-1) and a resonant frequency of 32 kHz; and a high speed lever with a spring constant of 50 pN nm(-1) and a resonant frequency of 1.8 MHz. Both these force sensors were fabricated by modifying commercial microcantilevers in a focused ion beam system. It is important to emphasize that these modified cantilevers could not be detected by the conventional optical detection system used in commercial atomic force microscopes.