Optical-trapping of particles in air using parabolic reflectors and a hollow laser beam

Optical trapping and light scattering in atmospheric aerosol science

“…Optical traps consisting of one or more hollow beams (that is, beams which have an intensity void in the centre) exploit the photophoretic force in order to achieve trapping of absorbing particles. 52,[67][68][69][70] However, examples of the use of these to characterise the optical properties of particles is limited. 52…”

Optical tweezers and manipulators. Modern concepts and future prospect

“…To achieve stable trapping, particularly of massive and large-size particles, counterpropagating beams are used. The combined action of oppositely directed scattering forces in such a trap compensates for their contribution; the counterpropagating beams can be formed separately, as well as by reflection of the initial trapping beam from a parabolic mirror placed behind the microscope objective focus [119].…”

“…Double-beam optical trap setups became widely used for problems concerning the capture of light-absorbing particles in free space (air and vacuum) [119,172]. In contrast to singlebeam traps based on gradient forces, they allowed creating conditions for trapping by scattering forces and mainly by the photophoretic force [169,173].…”

Tailored Transverse Mode Vertical-Cavity Surface-Emitting Laser: Hollow Laser Beam Emission through Circle Aperture

“…HLB is a laser beam that consists of a dark central region fully surrounded by regions of high intensity. The distinct properties of HLB promote its application to the optical-trapping of particles [12], laser-driven ion acceleration [13], and the generation of terahertz radiation [14]. Several general techniques for producing HLB are conical refraction [15,16], uniaxial crystal [17], interferometer [18], and photon sieve [19].…”