Sławomir Drobczyński and Kamila Duś-szachniewicz
In optical tweezers, the trap stiffness varies across the sample area. To avoid this problem, the force measurement is often performed in a fixed place where the trap stiffness is well determined. However, for some experiments, bringing the sample to the fixed position is problematic. In this paper, we describe a precise and fast procedure for mapping the trap stiffness over the whole sample area. Such a map allows development of a real-time procedure for force measurement at any point of the sample area. The presented method is particularly suitable for measuring forces, for example, in living cells samples.