CALCULATION OF THERMAL NOISE IN ATOMIC-FORCE MICROSCOPY
CALCULATION OF THERMAL NOISE IN ATOMIC-FORCE MICROSCOPY
复制标题
DOI：
10.1088/0957-4484/6/1/001
复制
发表时间：
1995-01-01
期刊：
影响因子：
3.5
通讯作者：
JASCHKE, M
中科院分区：
文献类型：
--
作者：
BUTT, HJ;JASCHKE, M
在原子力显微镜中，悬臂梁的热波动是噪声的一个基本来源。我们利用均分定理计算了悬臂梁的热噪声，并考虑了悬臂梁的所有可能的振动模式。热噪声的可测振幅取决于温度、悬臂梁的弹簧常数K和检测悬臂梁挠度的方法。如果直接测量挠度，例如使用干涉仪或扫描隧道显微镜，则可以从根kT/K计算具有自由端悬臂梁的热噪声。如果悬臂梁的末端由坚硬的表面支撑，则挠度的热波动是不可能的。如果采用光学杠杆技术测量挠度，则自由端悬臂梁的热噪声为根4kT/3K。悬臂梁有支撑时，热噪声减小到根kT/3K，但不消失。
Thermal fluctuations of the cantilever are a fundamental source of noise in atomic force microscopy. We calculated thermal noise using the equipartition theorem and considering all possible vibration modes of the cantilever. The measurable amplitude of thermal noise depends on the temperature, the spring constant K of the cantilever and on the method by which the cantilever deflection is detected. If the deflection is measured directly, e.g, with an interferometer or a scanning tunneling microscope, the thermal noise of a cantilever with a free end can be calculated from root kT/K. If the end of the cantilever is supported by a hard surface no thermal fluctuations of the deflection are possible. if the optical lever technique is applied to measure the deflection, the thermal noise of a cantilever with a free end is root 4kT/3K. When the cantilever is supported thermal noise decreases to root kT/3K, but it does not vanish.