Near-field Optical Microscopy Using High Q Factor Tuning Fork As Force Sensor

Near-field scanning optical microscopy has already been an important instrument in nanometer scale detect, one of the important component of a near-field scanning optical microscope is the feedback distance control. That maintains the tip at constant height above the sample especially using nonoptical means has been a hotspot question. Using tuning fork as force sensor has been an important means of nonoptical control for advantages such as high Q factor, low cost, simple configuration, high resolution etc. In this article, we describe an implementation of a tuning fork sensor suitable for AF/PSTM, we particularly discuss the principle of SNOM using tuning fork, design of high Q factor tuning fork/optical fiber force sensor, design of driving system of amplitude feedback using tuning fork and at last we discuss the question of the effect of the scale of optical fiber tip to the imaging.