Hollow Bessel-like beam as an optical guide for a stream of microscopic particles.

Current aerosol sample injection methods for coherent x-ray morphology suffer from excessive sample consumption due to the dispersion of the aerosol. To remedy this we propose here a high aspect ratio optical funnel by using a hollow Bessel-like beam with variable divergence, which may reduce sample consumption significantly. We present estimated optical forces exerted on the particles in the transverse plane, depending on various experimental conditions. We show that light pressure imposed by a funnel formed with 4.2 W continuous wave laser is sufficient to divert a stream of 2 µm polystyrene particles travelling ~50 m/s by ~1.5 × 10(-3) rad.