Characterisation and Calibration of Optical Tweezers [Mirror1]
Abstract
Using the optical tweezers, three different methods of calibrating the trap stiffness were performed: power spectrum fit, sinusoidal movement and finally a flow method. Iinitally in order to understand the equipment I have attempted to characterize the components of the optical tweezers. This involved measurements of laser stability, the stability of the sensors, external noise and measurements of particle size using dynamic light scattering. Initally the sinusodial method was favoured but due to problems with reproducability and complicated theory the flow method showed more promise. The theory behind the flow method is simple to understand and experimentally quite straight forward. Unfortunately due to time constraints further work will be required to verify this method.
Axial trapping showing two highly focused rays striking a particle symmetrically about its centre. The particle is shown below the focus point.
