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Proceedings Paper

Taking light pressure serious: light as a quasimechanical microtool
Author(s): Karl-Otto Greulich; Buerk Schaefer; Shamci Monajembashi
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Paper Abstract

Light pressure may arise from absorption and can then be calculated as pressure equals intensity / vacuum velocity of light. Alternatively, it may result from scattering and is then called gradient force. In that case a quality factor Q has to be introduced, which has to be determined by calibration. Its numerical value is between 0.05 and 0.3. By coupling a NdYAG laser into a microscope with a high numerical aperture objective scattering light pressure can be used to move micrometer-sized dielectric objects. Such optical tweezers can be calibrated and have been used to measure forces needed to stretch individual DNA molecules, and to measure forces exerted by the motor proteins myosin, kinesin and dynein non-calibrated optical tweezers are used to handle individual DNA molecules after their coupling to micrometer-sized microbeads. Using enzymes which cut DNA molecules in a sequence specific fingerprint-like pattern, it is possible to analyze DNA on a single molecule basis.

Paper Details

Date Published: 29 June 2001
PDF: 8 pages
Proc. SPIE 4430, ROMOPTO 2000: Sixth Conference on Optics, (29 June 2001); doi: 10.1117/12.432895
Show Author Affiliations
Karl-Otto Greulich, Institut fuer Molekulare Biotechnologie eV (Germany)
Buerk Schaefer, Institut fuer Molekulare Biotechnologie eV (Germany)
Shamci Monajembashi, Institut fuer Molekulare Biotechnologie eV (Germany)


Published in SPIE Proceedings Vol. 4430:
ROMOPTO 2000: Sixth Conference on Optics

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