Visualization 4-Optical tweezer experiment without flow.mp4

Visualization 4 shows the QPD signal and the particle motion image of 500 nm PS sphere measured in the trapping experiment without flow. At the beginning, the particles are doing intense unrestricted Brownian motion in the free solution. When the 976 nm laser is turned on (optical power is 30 mW), the particle is stably trapped and performs a small range of restricted Brownian motion in the potential well. The power spectral density curve can be obtained by the Fourier transform of the QPD signal. Furthermore, by manipulating the sample to move in the x and y direction through the stage, it can be observed that other particles in the field of view move with it, but the trapped particle is still stable confined in the potential well. When the laser is turned off, the particle is released and undergoes unrestricted Brownian motion again