Figure 1. Concept for monitoring the motion of a single nanowire in multi-dimensional directions.

(a) Optical tweezers setup with real-time dual particle tracking system (the ND filter and the piezo stage are not shown in this figure). The illumination beam on the SNW is propagated through two different paths by the beam splitter. In this case, two different images are projected on the chip of the CCD camera, each in half the total region (Inset image). (b) Geometry of the trapped SNW for measuring five degrees of freedom components. The image plane 1 (IP1) and 2 (IP2) can be moved by moving the tube lens L5 and L6. (c,d) Displacements in the x direction within IP1 (blue) and IP2 (green) plotted vs time and their distributions. The standard deviation of the displacement is 44.7 nm in IP1 and 68.7 nm in IP2.