Parametric Study of Folded Single Beam Traps

• Main Authors: Han-Chung Huang, 黃漢忠
• Other Authors: 邱爾德
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/60938472882354675303

碩士 === 國立東華大學 === 電機工程研究所 === 88 === Simultaneous multiple trapping of microparticles to form circular pattern in a Fold single beam traps (FSBT) is observed for the first time. A standing wave is formed due to the interference of incident wave coming from high-numerical aperture (NA) microscope objective lens and reflected wave from the a high reflectivity mirror. By changing the focus position of the trapping objective lens the size of the trapping volume and the strength of trapping force can be changed. We were able to trap up to sixteen particles of 5μm or six particles of 10μm or five particles of 20μm diameter in a circular pattern Simultaneously using FSBT. Trapping force measurements were performed using water viscous drag force method when the trapping beam focus was exactly on the mirror and also when the beam focus was above the mirror. Experimental results of trapping force measurements are presented by changing the laser power, the numerical aperture (NA) of the objective lens, and the particle size. Transverse trapping force measurements were also performed in a traditional single beam gradient force trap (SBGFT) and results are compared with the FSBT. It was found that trapping force is stronger in the case of FSBT as compare to SBGFT. The experimental results of FSBT are compared with the theoretical results using Ray-optics model for trapping particles using dual beam trap (DBGFT). Multiple trapping of microparticles using the Folded single beam trap is a simple and cost effective technique as compare to multiple optical tweezers currently used for pattern formation.