User:Pranav Rathi/Notebook/OT/2012/11/13/Optical Tweezers Calibration

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Revision as of 18:23, 14 November 2012 by Pranav Rathi (talk | contribs) (Laser)
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To perform accurate measurements with optical tweezers, it is necessary to calibrate some experimental parameters and even before that study the active components of the optical tweezers setup. The parameters I want to calibrate: Stiffness; which measures the force that is exerts on the trapped bead, and Sensitivity; which measures the relative position of bead within the trap. The components I want to study: Laser, AOM (acoustooptic module), objective, QPD (quadrant photo diode), z and x piezo. It is necessary to characterize these components first because not only they affect the experimental parameters but also reduce the chances to see something unexpected in data later on.


I characterized most of the active components in the setup starting with the laser.


It is important to know some facts about the laser used in the setup. I did not do a rigorous study (because it was not necessary), just specified few parameters like power output, beam waist and its location, polarization, beam mode profile and beam propagation factor. I used this information to design the tweezers. The laser specification are given in the following link: