<title>Polarization structure of combined vortex beams</title>

Internal flows and energy circulation in light beams

“…Quite similar manifestations of the azimuthal flows occur in other situations when a certain part of the beam cross section is artificially isolated by spatial obstacles. In particular, the well known patterns of diffraction by a slit [162,163] and by a non-transparent stripe [164,165] in beams with azimuthal transverse orbital flow are deformed (figure 20): The interference fringes bend in agreement with the local transverse momentum (or, which is the same, with the local velocity of the transverse energy transfer (7.5)). Of course, all these processes can be described in the diffraction language which is used in the original works [161][162][163][164][165] but employment of the transverse flows makes the behaviour physically clear and fairly spectacular.…”

“…Other examples of the same principle (LG beam transformations performed by an astigmatic lens [126], asymmetric telescopic transformations [45,127,128], or optical vortex generation with a misaligned 'fork' hologram [166]), confirm the general rule that visible evolution of the transformed beam spot carries the information on the internal energy flows before the symmetry breakdown. However, in most cases this relation is rather complicated and can only be used for qualitative indication of certain features of the energy flows, e.g., for detection of the azimuthal energy transfer and its predominant direction [77,161,164,165].…”

Localization and migration of phase singularities in the edge-diffracted optical-vortex beams

“…), which can be used in diverse metrological applications. Besides the rich and impressive physical contents, including the phase singularities, internal energy circulation, specific features of the linear and angular momentum distributions [4][5][6], such beams offer a wide range of perspective applications in the micromanipulation techniques [7][8][9][10], information transfer and processing [11,12], sensitivity and resolution enhancement in optical observations and measurements [13][14][15][16][17][18][19].Among diverse manifestations of the specific "circulational" properties of optical vortices, an important place belongs to the edge diffraction phenomena [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. A series of experimental and theoretical researches has demonstrated that diffraction "reveals" the internal energy circulation, normally "hidden" in circular OV beams, and induces the essential transformation of their phase profile.…”

“…Among diverse manifestations of the specific "circulational" properties of optical vortices, an important place belongs to the edge diffraction phenomena [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. A series of experimental and theoretical researches has demonstrated that diffraction "reveals" the internal energy circulation, normally "hidden" in circular OV beams, and induces the essential transformation of their phase profile.…”