dorsal/arxiv
View SchemaCalibration of optical tweezers with positional detection in the back-focal-plane
| Authors | Simon F. Tolic-Norrelykke, Erik Schaeffer, Jonathon Howard, Francesco S. Pavone, Frank Juelicher, Henrik Flyvbjerg |
|---|---|
| Categories | |
| ArXiv ID | physics/0603037 |
| URL | https://arxiv.org/abs/physics/0603037 |
| DOI | 10.1063/1.2356852 |
| Journal | Rev. Sci. Instrum. 77, 103101 (2006) (11 pages) |
Abstract
We explain and demonstrate a new method of force- and position-calibration for optical tweezers with back-focal-plane photo detection. The method combines power spectral measurements of thermal motion and the response to a sinusoidal motion of a translation stage. It consequently does not use the drag coefficient of the trapped ob ject as an input. Thus, neither the viscosity, nor the size of the trapped ob ject, nor its distance to nearby surfaces need to be known. The method requires only a low level of instrumentation and can be applied in situ in all spatial dimensions. It is both accurate and precise: true values are returned, with small error-bars. We tested this experimentally, near and far from surfaces. Both position- and force-calibration were accurate to within 3%. To calibrate, we moved the sample with a piezo-electric translation stage, but the laser beam could be moved instead, e.g. by acousto-optic deflectors. Near surfaces, this precision requires an improved formula for the hydrodynamical interaction between an infinite plane and a micro-sphere in non-constant motion parallel to it. We give such a formula.
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"abstract": "We explain and demonstrate a new method of force- and position-calibration\nfor optical tweezers with back-focal-plane photo detection. The method combines\npower spectral measurements of thermal motion and the response to a sinusoidal\nmotion of a translation stage. It consequently does not use the drag\ncoefficient of the trapped ob ject as an input. Thus, neither the viscosity,\nnor the size of the trapped ob ject, nor its distance to nearby surfaces need\nto be known. The method requires only a low level of instrumentation and can be\napplied in situ in all spatial dimensions. It is both accurate and precise:\ntrue values are returned, with small error-bars. We tested this experimentally,\nnear and far from surfaces. Both position- and force-calibration were accurate\nto within 3%. To calibrate, we moved the sample with a piezo-electric\ntranslation stage, but the laser beam could be moved instead, e.g. by\nacousto-optic deflectors. Near surfaces, this precision requires an improved\nformula for the hydrodynamical interaction between an infinite plane and a\nmicro-sphere in non-constant motion parallel to it. We give such a formula.",
"arxiv_id": "physics/0603037",
"authors": [
"Simon F. Tolic-Norrelykke",
"Erik Schaeffer",
"Jonathon Howard",
"Francesco S. Pavone",
"Frank Juelicher",
"Henrik Flyvbjerg"
],
"categories": [
"physics.bio-ph",
"physics.ins-det",
"q-bio.QM"
],
"doi": "10.1063/1.2356852",
"journal_ref": "Rev. Sci. Instrum. 77, 103101 (2006) (11 pages)",
"title": "Calibration of optical tweezers with positional detection in the back-focal-plane",
"url": "https://arxiv.org/abs/physics/0603037"
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