1. Near-field optical micromanipulation with cavity enhanced evanescent waves Prepared by David Keng Nov. 3, 2006 Peter J. Reece,a Veneranda Garcés-Chávez, and Kishan Dholakia School of Physics and Astronomy, University of St Andrews, Saint Andrews, Fife KY16 9SS, Scotland, United Kingdom

2. Important things in this paper Near-field optical micromanipulation with cavity enhanced evanescent waves Near-field optical micromanipulation cavity enhanced evanescent waves

3. Near-field optical micromanipulation Optical guiding and/or trapping particle with evanescent waves

4. Near-field optical micromanipulation In this paper…1064 nm CW laser (4 W, IPG Yb doped fiber laser) Velocity of 5 m polymer colloids at a BK7 glass-water interface… ~4 um/s 1.8W focused to a 200um spot (without enhancement layer!) With enhancement layer… 22±2.7 um/s!! 1.8 W / (2 x 10 -4 m) 2 = 4.5 x 10 7 W/m 2 Theirs… 0.005 W / (4 x 10 -6 m) 2 = 3.1 x 10 8 W/m 2 Inside MP3L tapered fiber

5. Conclusion for Near-field optical micromanipulation To guide a particle… particle trapped within E.W. above surface To trap a particle… two counter propagating waves Larger the particle size… easier to trap smaller the Brownian motion (high drag) higher polarizability (stronger trapping force) Should be able to perform on the tapered fiber…

6. H2O Enhancement “dielectric resonator” Looks like this… SF11 SiO2 1000nm ZrO2 127nm 1.7541.451.971.33

7. Enhancement Light is launched into the 127nm layer 32 times of the incident intensity in the layer 25 times at the surface 5~10 times measured… v = 2~4 vs. 22