Open AccessDepth-Dependent Optical Stiffness Toward Water-Air Interface
Author(s) -
Muhamad Safuan Mat Yeng,
Shahrul Kadri Ayop,
Izan Roshawaty Mustapa
Publication year - 2018
Publication title -
international journal of engineering and technology
Language(s) - English
Resource type - Journals
ISSN - 2227-524X
DOI - 10.14419/ijet.v7i4.30.22019
Subject(s) - optical tweezers , materials science , optics , laser , stiffness , radius , optical power , trapping , bead , polystyrene , wavelength , focus (optics) , laser power scaling , optoelectronics , composite material , physics , ecology , computer security , computer science , biology , polymer
This research attempted to quantify the optical stiffness of trapped polystyrene bead toward water-air interface. The optical tweezers with 975 nm wavelength was used to optically trap a single 3 micron diameter of bead in a water-contained cell with air exposed top water surface. The optical stiffness was justified on effective radius (r*) of the bead lateral spatial distribution. The scattered light signals due to the trapped bead at different laser focus height from the bottom glass-water interface (less than 20 µm) and laser trapping powers (1.7 mW to 7.5 mW) were analyzed to investigate the r* profile. It was found that within our experimental condition, r* was independent of focus height at fixed power and exponentially decay with respect to laser power at fixed focus height.