RT - Journal Article T1 - Optical trapping by radially and azimuthally polarized beams JF - opsi YR - 2017 JO - opsi VO - 23 IS - 0 UR - http://opsi.ir/article-1-1133-en.html SP - 429 EP - 432 K1 - Optical tweezers K1 - trap stiffness K1 - cylindrical vector beam K1 - radial polarization K1 - azimuthal polarization AB - Implementing laser beams possessing desired spatial structure can provide a potential to control optical forces of optical tweezers in the trapping of micro and nanoparticles. Cylindrical vector beams, in particular, are good candidates due to their exotic optical features. For instance, a radially polarized beam generates a focus volume about 30 percent smaller than that of a Gaussian beam. Here, we experimentally study the optical trapping stiffness for both cases of micro- and nanometer particles. The results for 2.1-micron polystyrene beads show that the trapping force in the axial direction is ~3 times stronger for the radial polarization than that of a linear polarized beam. Finally, we show that such improvement in trapping depends on the size of the trapped particle. LA eng UL http://opsi.ir/article-1-1133-en.html M3 ER -