Ultraviolet broadband light scattering for single optically-trapped submicron- sized aerosol particles
نویسندگان
چکیده
The QBB trap (left panel in Fig. A) is composed of two perpendicularly arranged counterpropagating Bessel beam (CPBB) traps6, 7. The two sets of CPBB traps are obtained by splitting the beam from the trapping laser (Laser Quantum, OPUS 3 532 nm, typical power: 1000 mW) into two beams using a half-wave plate (λ/2) and a polarization beam splitter cube (PBC). From each of these two beams, a Bessel beam (BB) is formed with a 178° apex angle axicon (Altechna, 1-APX-1-H254). Each of these two BBs is then split again into two beams by λ/2 plates and PBCs to obtain the two counter-propagating BBs (BB1/BB2 and BB3/BB4), which are cross-polarized and have equal intensity. Each BB is mapped to the centre of the trapping cell by a telescope that consists of two lenses with 500 and 75 mm focal length, respectively. The core radii of the BBs in the trap centre are 3.36 μm. The typical total light intensity in the trap centre is 2.6 J s−1 μm−2 for perfect alignment.
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