METHOD FOR INCREASING SHEAR-FORCE DETECTION SENSITIVITY WITH UNCOATEDFIBER TIPS

A technique that is easy to implement and sensitive for measuring late ral oscillation amplitudes of optical fibers on the nanometer scale fo r shear-force microscopy is described. The measurement system analyzed here is based on using the optical fiber tip as a cylindrical lens to focus and deflect a detection beam. It is shown that for our experime ntal arrangement, this technique is at least 2.5 times as sensitive as merely shadowing the edge of such a beam, as in most commonly used co nfigurations. As a result, oscillation amplitudes of the order of 2-3 nm may easily be measured. An advantage of this system is that absolut e vibration amplitudes are easily measured. A simple geometric model i s used to describe the operation of the system. (C) 1997 Optical Socie ty of America.