To see new Physics, we must move from trapping in the air to trapping in a vacuum. Unfortunately, the small gap between the fibre ferrules leads to a large pressure difference as the air is pumped away, which blows the bead out of the trap. To overcome this problem we will trap using beams focused by aspheric lenses. A schematic is shown below.

Lens trap

The bead can be trapped at the focus, or, by separating the beams slightly, we recover the same trapping geometry as before (lower diagram in the image above).

In the video “Lens trapping” you can clearly see the shape of the trapping beams as beads are sprayed into the trap region (the beams are aligned vertically in this image). This video shows a trapping attempt, beads are clearly visible at the focus, but the alignment / stability has not yet been perfected.

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