  We introduce a novel approach for all-optical trapping and manipulation of
absorbing aerosol particles based on a photophoretic force. We demonstrate
experimentally, in open air, the robust three-dimensional guiding of
agglomerates of carbon nanoparticles with the size spanned for two orders of
magnitude, from 100 nanometers to 10 microns, over the distances of a few
millimeters, as well as their acceleration up to velocities of 1 cm/s and
simultaneous trapping of a large number of particles.
