26 research outputs found
Low-temperature laser-stimulated controllable generation of micro-bubbles in a water suspension of absorptive colloid particles
Orbital rotation without orbital angular momentum: mechanical action of the spin part of the internal energy flow in light beams
It is known that internal energy flow in a light beam can be divided into the
orbital flow, associated with the macroscopic energy redistribution within the
beam, and the spin flow originating from instantaneous rotation of the field
vectors inherent in circular or elliptic polarization. In contrast to the
orbital one, experimental observation of the spin flow constituent seemed
problematic because (i) it does not manifest itself in the visible
transformation of the beam profile and (ii) it converts into the orbital flow
upon tight focusing of the beam, usually employed for the energy flow detection
by the mechanical action on probe particles. We propose a two-beam interference
technique that permits to obtain appreciable level of the spin flow in
moderately focused beams and to detect the orbital motion of probe particles
within a field where the transverse energy circulation is associated
exclusively with the spin flow. This result can be treated as the first
demonstration of mechanical action of the spin flow of a light field.Comment: 9 pages, 3 figures and 1 video cli
Controllable generation and manipulation of micro-bubbles in water with absorptive colloid particles by CW laser radiation
Measurement of small light absorption in microparticles by means of optically induced rotation
Experimental demonstration of singular-optical colouring of regularly scattered white light
Experimental interference modelling of the effects of colouring of a beam traversing a light-scattering medium is presented. It is shown that the result of colouring of the beam at the output of the medium depends on the magnitudes of the phase delays of the singly forward scattered partial signals. The colouring mechanism has for the first time experimentally been illustrated for a forward propagating beam through a light-scattering medium. This is showed in video-fragments of the interferograms recorded within the zero interference fringe with a gradual change of the path difference of the interfering polychromatic wave trains. Spectral investigation of the effects of colouring has been carried out using a solution of liquid crystal in a polymer matrix. The amplitude ratio of the non-scattered and the singly forward scattered interfering components significantly affects the colour intensity. It has further been established that the spectral content of the illuminating beam strongly influences the colour of the resulting radiation