We currently load our trap with a nebulizer; beads are suspended in methanol, and then forced through a fine mesh to create a mist of microspheres. This is an unreliable loading mechanism, and beads tend to get stuck to everything, as can be seen in the photo below, where spheres are stuck to a fibre.

Fibre + beads

The video “Sticky beads” shows a trapping attempt between two fibres, where the bead ends up sticking to the end of one fibre (on the left), which makes future trapping impossible. At this point the fibre must be cleaned, polished or re-cleaved.

We wish to manipulate beads into the trapping region using laser light, as done by Horstmann et al. (Appl. Phys. B 103 35-39 (2010). The video “Bead train” shows beads moving in a focused beam.

We have designed a small glass cell, into which a mist of beads can be sprayed. They are then guided out of the cell through a small hole, as shown in the video “Bead gun”. In this video the cell is on the right, and open air is on the left, so the beads are moving right to left. The hole will be replaced by glass capillaries, to guide the beads.

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