Gates Richard S, Osborn William A, Shaw Gordon A
Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
Nanotechnology. 2015 Jun 12;26(23):235704. doi: 10.1088/0957-4484/26/23/235704. Epub 2015 May 20.
Calibration of the flexural spring constant for atomic force microscope (AFM) colloid probe cantilevers provides significant challenges. The presence of a large attached spherical added mass complicates many of the more common calibration techniques such as reference cantilever, Sader, and added mass. Even the most promising option, AFM thermal calibration, can encounter difficulties during the optical lever sensitivity measurement due to strong adhesion and friction between the sphere and a surface. This may cause buckling of the end of the cantilever and hysteresis in the approach-retract curves resulting in increased uncertainty in the calibration. Most recently, a laser Doppler vibrometry thermal method has been used to accurately calibrate the normal spring constant of a wide variety of tipped and tipless commercial cantilevers. This paper describes a variant of the technique, scanning laser Doppler vibrometry, optimized for colloid probe cantilevers and capable of spring constant calibration uncertainties near ±1%.
校准原子力显微镜（AFM）胶体探针悬臂的弯曲弹簧常数面临重大挑战。附着有大的球形附加质量会使许多更常见的校准技术变得复杂，比如参考悬臂法、萨德法和附加质量法。即使是最有前景的方法——AFM热校准，在光学杠杆灵敏度测量过程中也可能会遇到困难，因为球体与表面之间存在很强的附着力和摩擦力。这可能会导致悬臂末端弯曲以及接近 - 回缩曲线出现滞后现象，从而增加校准的不确定性。最近，激光多普勒振动测量热方法已被用于精确校准各种有针尖和无针尖的商用悬臂的法向弹簧常数。本文描述了该技术的一种变体——扫描激光多普勒振动测量法，它针对胶体探针悬臂进行了优化，并且弹簧常数校准不确定度接近±1%。
