We have trapped a 2.5 micron diameter bead in air and reduced the pressure to 0.1mbar, that’s a reduction in pressure of four orders of magnitude! At this pressure the oscillation of the bead in the trap is visible; at higher pressures it is damped by the presence of air. A video can be seen below:



We also have a new imaging system, with improved zoom capabilities. In the image below you can see the mounts for the aspheric lenses, and between them the out of focus image of a trapped bead.


Trapped bead and lens holders


Next step: characterizing trap oscillations using a quadrant photodiode, and introduce some feedback stabilization to reach lower pressures.