Publications by authors named "Ann A M Bui"
Force measurement with an optical trap requires calibration of it. With a suitable detector, such as a position-sensitive detector (PSD), it is possible to calibrate the detector so that the force can be measured for arbitrary particles and arbitrary beams without further calibration; such a calibration can be called an "absolute calibration". Here, we present a simple method for the absolute calibration of a PSD.
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- - This study explores how external forces can help trapped particles escape from optical tweezers, providing a method to quantitatively measure optical forces based on trapping power and particle position within the trap's edge.
- - By examining how a trapped particle’s escape trajectory is affected by fluid flow acceleration, the research finds that particles don't always escape in a straight line, potentially leading to significant variations in the escape force needed for calibration.
- - The work combines computational simulations and experimental data to demonstrate that escape force efficiency can vary substantially—up to 20%—depending on both the rate of force application and trapping power, which can influence calibration accuracy.
Quantitative determination of the motility forces of chromosomes during cell division is fundamental to understanding a process that is universal among eukaryotic organisms. Using an optical tweezers system, isolated mammalian chromosomes were held in a 1064 nm laser trap. The minimum force required to move a single chromosome was determined to be ≈ 0.
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- - Nonspherical probe particles can be effectively used in optically-trapped scanning probe microscopy.
- - The calibration of the trap can be achieved using only position data, eliminating the need to measure the particle's orientation.
- - The method relies on a pseudopotential derived from position occupation probabilities, without needing to assume a linear relationship between force and displacement.