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Updated: May 27, 2026
08:57
Optical Trap Loading of Dielectric Microparticles In Air
Published on: February 5, 2017
Noise associated with nonconservative forces in optical traps.
Michel de Messieres1, Natalia A Denesyuk, Arthur La Porta
1Department of Physics, Institute for Physical Science and Technology Biophysics Program, University of Maryland, College Park, Maryland 20742, USA.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|November 9, 2011
Summary
Thermal fluctuations in optical traps can create nonequilibrium effects. This study quantizes these fluctuations, finding they are minimal in typical biophysical experiments involving DNA.
Area of Science:
- Physics, Optics
- Biophysics
- Statistical Mechanics
Background:
- Optical traps are widely used to manipulate microscopic particles.
- Nonconservative forces in optical traps can lead to persistent nonequilibrium phenomena.
- Understanding thermal fluctuations is crucial for precise measurements in biophysics.
Purpose of the Study:
- To analytically and computationally investigate position fluctuations caused by nonequilibrium flux in optical traps.
- To develop a model that quantifies additional fluctuations due to nonconservative scattering forces.
- To assess the impact of these fluctuations on biophysical measurements, such as DNA tether length.
Main Methods:
- Analytical calculations of position fluctuations.
- Computer simulations to model nonequilibrium effects.
- Development of a closed-form solution for additional fluctuations.
- Simulated biophysical experiment measuring DNA tether length fluctuations.
Main Results:
- A model was developed that reproduces nonequilibrium effects in optical traps.
- The magnitude of additional position fluctuations was calculated.
- The ratio of nonconservative to thermal fluctuations scales inversely with the square root of trap power.
- Nonconservative forces did not significantly increase fluctuations in simulated DNA tether length experiments.
Conclusions:
- Nonconservative scattering forces can induce additional position fluctuations in optical traps.
- These additional fluctuations are generally small under typical experimental conditions.
- The findings suggest that nonconservative forces have a limited impact on the precision of biophysical measurements like DNA mechanics.
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