Particles transparent, optical trapping

The LS theory was applied to the localization of a Brownian particle in a three-dimensional optical trap [89] a transparent dielectric spherical silica particle of diameter 0.6 pm suspended in a liquid [88]. The particle moves at random within the potential well created with a gradient three-dimensional optical trap—a technique widely used in biophysical studies. The potential was modulated by a biharmonic force. By changing the phase shift between the two harmonics it was possible to localize the particle in one of the wells in very good quantitative agreement with the predictions based on the LS. 

Although the particles normally trapped with optical tweezers are highly transparent, there is usuaUy some absorption occurring. Studies have been made of the wavelength dependence of the heating of specimens and the ability of live specimens to remain viable after having been trapped [14,15,16]. 

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