How orbital angular momentum affects beam shifts in optical reflection

Merano, Michele; Hermosa, Nathaniel; Woerdman, J. P.; Aiello, Andrea

doi:10.1103/physreva.82.023817

Cited by 179 publications

(165 citation statements)

References 29 publications

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“…We see that, as the incident angle passes through the critical angle, the shift diverges and changes sign-as theory predicts. The apparent systematic deviation is probably due to interface imperfections, as has been observed many times before (e.g., [9,10]). …”

Section: Methodssupporting

confidence: 60%

An experiment on the shifts of reflected C-lines

Löffler¹,

Nye²,

Hannay³

2014

J. Opt.

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Löffler et al., An experiment on the shifts of reflected C--lines 2 Abstract An experiment is described that tests theoretical predictions on how C--lines incident obliquely on a surface behave on reflection. C--lines in a polarised wave are the analogues of the optical vortices carried by a complex scalar wave, which is the usual model for describing light and other electromagnetic waves. The centre of a laser beam that carries a (degenerate) C--line is shifted on reflection by the well--known Goos--Hänchen and Imbert--Fedorov effects, but the C--line itself splits into two, both of which are shifted longitudinally and laterally; their shifts are different from that of the beam centre. To maximise the effect to be measured, internal reflection in a glass prism close to the critical angle was used. In a simple situation like this two recently published independent theories of C--line reflection overlap and it is shown that their predictions are identical. The measured differences in the lateral shifts of the two reflected C--lines are compared with theoretical expectations over a range of incidence angles. IntroductionWave dislocations [1,2] or optical vortices as they are now called, lines of zero disturbance, are features in the complex scalar fields commonly used to represent light. The phase circulates around them in the manner of a vortex. They occur generically, that is, they appear naturally in any general monochromatic scalar field. However, in the vector electromagnetic field that fully describes light, including its polarization, the end of the electric vector at each point describes a polarization ellipse, which collapses to zero only at special points; zeros are not generic. A feature in a vector wavefield that is generic and may be thought of as the counterpart of the line vortex in scalar waves is a line where the polarization ellipse is a circle, a CT--line (T for true). The polarization ellipse observed on a screen is not this but its projection. Points appear on the screen, C--points, where the observed projected polarization is a circle, and as the screen is moved parallel to itself the points trace out lines, C--lines, in space. It is these C--lines that are the concern of this paper.Previous papers [3][4][5] examined theoretically what happens when a laser beam containing a C--line is incident at an angle on a single plane interface between two different media. The usual Fresnel coefficients cannot be used directly here because they apply to a simple plane wave. Instead, the first of these theoretical papers and the last pair describe alternative schemes, each being a slightly different idealization of the core of the beam and each having its own advantages. The two schemes overlap, however, for a suitable simple beam, and this case is considered here -the experiment thereby acts to confirm both. It suffices to describe this overlap case by one of the two schemes-we choose the differentiated plane wave (DPW) approach and relate it to the other scheme briefly in an Appendix.Löffler et al., An ...

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Section: Methodssupporting

confidence: 60%

An experiment on the shifts of reflected C-lines

Löffler¹,

Nye²,

Hannay³

2014

J. Opt.

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“…The realization that light beams can have quantized orbital angular momentum in addition to spin angular momentum has led, in recent years, to novel experiments in quantum and classical optics [1,2,3,4], new methods for manipulating micro particles [5,6], new possibilities in optical metrology [7,8] and new ways to boost the capacity of communication channel [9] to name a few of the many exciting applications of these beams. Optical beams with OAM are best prepared with helically phased light beams, such as the Laguerre Gaussian (LG) modes, which have an explicit φ phase factor, where is the topological charge and φ is the azimuthal coordinate [10,11].…”

Section: Introductionmentioning

confidence: 99%

OAM beams from incomplete computer generated holograms projected onto a DMD

2017

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We show that optical beams with orbital angular momentum (OAM) can be generated even with incomplete computer generated holograms (CGH). These holograms are made such that random portions of it do not contain any information. We observe that although the beams produced with these holograms are less intense, these beams maintain their shape and that their topological charges are not affected. Furthermore, we show that superposition of two or more beams can be created using separate incomplete CGHs interspersed together. Our result is significant especially since most method to generate beams with OAM for various applications rely on pixelated devices or optical elements with imperfections.

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“…Both shifts have been extensively studied theoretical and experimentally for a wide number of beam configurations and interfaces. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] In the present work we obtain closed and simple expressions that provide the relation between the GH shift and the global spatial structure of a totally polarized partially coherent beam, within the framework of the second-order irradiance moments. [21][22][23][24][25][26] This paper is organized as follows.…”

Section: Introductionmentioning

confidence: 99%