Figure 5.

(a) Schematic of the optical trapping apparatus used to trap both transparent and absorbing airborne particles of arbitrary morphology using a single shaped hollow laser beam. The aspheric lens forms a hollow conical focus within a glass chamber where airborne particles are trapped; (b) Calculated intensity profile near the focal spot plotted on a log-scale; (c) Image of the conical focal region produced inside the chamber obtained by introducing Johnson Smut Grass Spores and recording a long exposure time image; (d) Image of a spore trapped in air near the focal point [44] (Fair Use according to OSA).