Arvind Balijepalli, Jason J Gorman, Satyandra K. Gupta, and Thomas W. LeBrun
We demonstrate an increase in trapping lifetime for optically trapped nanoparticles by more than an order of magnitude using feedback control with no corresponding increase in beam power. Langevin dynamics simulations were used to design the control law and this technique was then demonstrated experimentally for 100 nm gold particles and 350 nm silica particles. No particle escapes were detected with the controller on, leading to lower limits on the increase in lifetime for the 100 nm gold particles of 26 times (at constant average beam power) and 22 times for the 350 nm silica particles (with average beam power reduced by one third). The approach described here can be combined with other techniques such as counter propagating beams or higher-order optical modes to trap the smallest nanoparticles, and can be used to reduce optical heating of particles that are susceptible to photodamage, such as biological systems.
DOI
We demonstrate an increase in trapping lifetime for optically trapped nanoparticles by more than an order of magnitude using feedback control with no corresponding increase in beam power. Langevin dynamics simulations were used to design the control law and this technique was then demonstrated experimentally for 100 nm gold particles and 350 nm silica particles. No particle escapes were detected with the controller on, leading to lower limits on the increase in lifetime for the 100 nm gold particles of 26 times (at constant average beam power) and 22 times for the 350 nm silica particles (with average beam power reduced by one third). The approach described here can be combined with other techniques such as counter propagating beams or higher-order optical modes to trap the smallest nanoparticles, and can be used to reduce optical heating of particles that are susceptible to photodamage, such as biological systems.
DOI
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