Calibration of optical tweezers with differential interference contrast signals

A comparison of different calibration methods for optical tweezers with the differential interference contrast (DIC) technique was performed to establish the uses and the advantages of each method. A detailed experimental and theoretical analysis of each method was performed with emphasis on the anisotropy involved in the DIC technique and the noise components in the detection. Finally, a time of flight method that permits the reconstruction of the optical potential well was demonstrated. (C) 2002 American Institute of Physics.