Tunable, anomalous Mie scattering using spatial coherence

Abstract

We demonstrate that a J0-Bessel-correlated beam that is incident on a homogeneous sphere produces a highly unusual distribution of the scattered field, with the maximum no longer occurring in the forward direction. Such a beam can be easily generated using a spatially incoherent, annular source. Moreover, the direction of maximal scattering can be shifted by changing the spatial coherence length. In this process, the total power that is scattered remains constant. This new tool to control scattering directionality may be used to steer the scattered field away from the forward direction and selectively address detectors situated at different angles.

Strong suppression of forward or backward Mie scattering by using spatial coherence

“…We recently demonstrated that a J 0 Bessel-correlated beam, which is incident on a homogeneous sphere, produces a highly unusual distribution of the scattered field [19]. In the present study we derive expressions that relate the scattered field for this particular case to that of an incident field that is spatially fully coherent.…”

“…We also remark that the near-zero scattering in the forward direction that we obtain does not violate the optical theorem. This issue was addressed in [19].…”

“…In a previous publication [19], we derived that in the case of a J 0 -correlated field, the angular distribution of the intensity of the scattered field is given by the expression…”

“…It was shown in [19] that the total scattered power remains constant when the coherence parameter β∕k is varied. This means that the scattered intensity is merely redistributed.…”

Generation of Vector Partially Coherent Optical Sources Using Phase-Only Spatial Light Modulators

“…Their widespread appeal stems from the fact that, by simply manipulating spatial coherence, the source's resulting shape and polarization can be precisely controlled. Numerous researchers have designed vector partially coherent sources for applications such as free-space and underwater optical communications [7][8][9][10][11][12][13][14][15][16], remote sensing [17,18], optical scattering [19][20][21][22][23][24][25][26][27][28][29], and particle manipulation and trapping [30][31][32][33].…”