| |
| author |
Matheus Macena de Carvalho
| | title |
Single-Laser Optical Tweezers:
Background, Applications, and Calibration
Methods
| | abstract |
Through the studies of radiation pressure and using recently developed laser technologies,
optical tweezers were invented by Dr. Arthur Ashkin. Recent biological and quantum
physics applications motivated the study of optical trapping systems at Drew University.
During Drew Summer Science Institute in 2019, 1 micron polystyrene beads were
recorded trapped and manipulated on the sample plane of a custom-made optical
tweezers setup. The bulk of the setup was then replaced by a Zeiss Axioplan
2 microscope to attempt measuring the trapping stiffness applied on the beads.
Multiple calibration methods are addressed and the feasibility of their implementation
is discussed. Both theoretical, Rayleigh Regime, and experimental calibration methods,
Brownian Harmonic Oscillator, are used to quantitatively determine the trapping
stiffness of a system. Although the Rayleigh Regime makes an approximation for
beads not in this study's range, it serves as a basis of comparison to the experimental
data. Through the use of a quadrant photodiode, the Brownian Harmonic Oscillator
method analyzes the thermal fluctuations of a trapped bead. These fluctuations are
converted into frequencies, which are linearly proportional to the trapping stiffness.
The theoretical, and experimental calibration methods yield similar results, in the
same order of magnitude, and increase the trapping stiffness with greater laser power.
Future applications to increase the reliability of the system calibration, such as the
calibration of the quadrant photodiode, parameters variations, and new calibration
methods are then addressed.
| | school |
The College of Liberal Arts, Drew University
| | degree |
B.S. (2021)
|
| advisor |
Bjorg Larson
|
| committee |
Jim Supplee
Brianne Barker
|
| full text | MMacenadeCarvalho.pdf |
| |
