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Tag Archives: optical tweezers

Lambda exonuclease video

Wednesday, August 3, 2011

The fourth paper from my thesis, entitled "Dual-trap optical tweezers with real-time force clamp control", has just been published online by Review of Scientific Instruments: http://link.aip.org/link/doi/10.1063/1.3615309 Here's a video from the paper. We are holding on to two micron sized plastic spheres with laser-beams (shown in the video as green/cyan cross-hairs). The lower beam/trap is [...]

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Force-clamp feedback for optical tweezers

Tuesday, February 22, 2011

A ~16 um long DNA-molecule is tethered between optically trapped plastic beads. Beads are held by a stationary trap (lower blue cross-hairs) and a steerable trap (upper green cross-hairs). The graphs on the right show the measured force (red) and the force set-point (blue) (top), the distance between the traps (middle), and the force-extension curve [...]

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One More Feedback Paper

Tuesday, November 10, 2009

FPGA-based real-time position-clamp control in optical tweezers, The Sequel: doi:10.1063/1.3257693 (first part here)

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Fluorescent DNA

Tuesday, October 27, 2009

Some very early testing of fluorescence imaging in our optical tweezers instrument. A 10 kb long piece of DNA (ca 3 um long when stretched) is held between two optically trapped microspheres. The DNA is coated with a fluorescent dye (SYBR-gold) which is exited by a 488 nm blue laser and the fluorescence signal is [...]

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playing with entangled beads in optical tweezers

Tuesday, January 27, 2009

Were stretching a 13 kb DNA-construct between two optically trapped beads. This isn't a video of the experiment itself, but of some entangled beads we found in an old sample. The beads are 3 or 2 micron in diameter, and we hold on to the middle big bead with the optical trap while moving around [...]

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An optical position clamp

Monday, June 9, 2008

Optical tweezers use light to trap dielectric particles in an approximately harmonic potential. If the position of the bead is X, the position of the trap Xtrap, and the stiffness of the trap k then the equation of motion looks like this: where Beta is the drag coefficient and Ft is a random white-noise thermal [...]

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