Application of BP neural network to nonlinearity correction of optical tweezer force

The Back-Propagation(BP) neural network was proposed to correct the nonlinearity and to optimize the force measurement and calibration of an optical tweezer system.Considering the low convergence rate of the BP algorithm,the Levenberg Marquardt(LM) algorithm was used to improve the BP network.The proposed method was experimentally studied for force calibration in a typical optical tweezer system using the hydromechanic methods.The result shows that with the nonlinearity correction using BP neural network,the range of force measurement of an optical tweezer system is enlarged by 30% and the precision is also improved comparing with polynomial fitting method.It is demonstrated that the nonlinearty correction by neural network method improves effectively the performance of optical tweezers without adding or changing measuring system.