A1. Pioneering work For a linearly polarized laser mode:
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Getting started on Orbital Angular Momentum of Light
A1. Pioneering work
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Getting started on Orbital Angular Momentum of Light
[15]Phys. Rev. A 54 (2): 1593–1596 [17]Nature Physics 4 (4): 282
[16]Optics Express 12 (22): 5448–56 [18]Optics Letters 30 (24): 3308–10
34
Application
C2. Merits Qunits (sometimes qudits)
17
Getting started on Orbital Angular Momentum of Light
A3.Amplitude and phase
18
Outline
Getting started on Orbital Angular Momentum of Light
Making helical phasefronts Application Conclusions
[12] Phys. Rev. Lett. 96,163905 [13]Applied Physics Letters 94 (23): 231124 31
Making helical phasefronts B4. Cylindrical Mode Converters
OAM can also be generated by converting Hermite-Gaussian beams into the Laguerre-Gaussian ones by using an astigmatic system with two well-aligned cylindrical lenses placed at a specific distance (see figure) in order to introduce a well-defined relative phase between horizontal and vertical Hermite-Gauss beams.[14]
[14] Phys. Rev. A 45 (11): 8185–8189
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Outline
Getting started on Orbital Angular Momentum of Light
Making helical phasefronts Application Conclusions
20
Making helical phasefronts B1. Spiral Phase Plate (SPP)
Optics Communication 112 (5–6): 321
21
Making helical phasefronts B1. Spiral Phase Plate (SPP)
(III)Pitch-Fork Hologram
Modulator: phase and intensity
Ref. PHD_2011 B.Jack
30
Making helical phasefronts B3. Q-Plate
Another method for generating OAM is based on the SAM-OAM coupling that may occur in a medium which is both anisotropic and inhomogeneous. In particular, the so-called q-plate is a device, currently realized using liquid crystals, polymers or sub-wavelength gratings, which can generate OAM by exploiting a SAM sign-change. In this case, the OAM sign is controlled by the input polarization.[12][13]
A2.Orbital Angular Momentum from helical phase fronts Calculate AM from EM field
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Getting started on Orbital Angular Momentum of Light
A2.Orbital Angular Momentum from helical phase fronts
Spin angular momentum
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Getting started on Orbital Angular Momentum of Light
A2.Orbital Angular Momentum from helical phase fronts
Orbital angular momentum
15
Getting started on Orbital Angular Momentum of Light
A3.Amplitude and phase Amplitude:
16
Getting started on Orbital Angular Momentum of Light
A3.Amplitude and phase Phase:
3.Higher-dimensional quantum information encoding, for possible future quantum cryptography or quantum computation applications[17] 4. Sensitive optical detection [18]
3
Outline
Getting started on Orbital Angular Momentum of Light
Making helical phasefronts Application Conclusions
4
Getting started on Orbital Angular Momentum of Light
A1. Pioneering work
The linear momentum density:
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Getting started on Orbital Angular Momentum of Light
A1. Pioneering work For arbitrary polarization:
The linear momentum density:
19
Making helical phasefronts B1. Spiral Phase Plate (SPP) A light beam can acquire OAM by crossing a spiral phase plate, with a inhomogeneous thickness
(III)Pitch-Fork Hologram
Modulator: phase
Ref. PHD_2011 B.Jack
28
Making helical phasefronts B2. Hologram
(III)Pitch-Fork Hologram
Modulator: phase
29
Making helical phasefronts B2. Hologram
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Application
C1. Introduction
1.Orientational manipulation of particles or particle aggregates in optical tweezers[15]
2.High-bandwidth information encoding in free-space optical communication [16]
A1. Pioneering work
Professor Les Allen
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Getting started on Orbital Angular Momentum of Light
A1. Pioneering work Formalism:
6
Getting started on Orbital Angular Momentum of Light
[7]JETP Letters 52 (8): 429. [8]Journal of Modern Optics 39 (5): 985 [9]Optical and Quantum Electronics 24 (9): S951 [10]Phys. Rev. A 56 (5): 4064
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[11]Optics Letters 17 (3): 221
Orbital Angular Momentum of Photons
1
2
Outline
Getting started on Orbital Angular Momentum of Light
Making helical phasefronts Application Conclusions
(II)Spiral phase hologram:
Ref. PHD_2011 B.Jack
26
Making helical phasefronts B2. Hologram
(II)Spiral phase hologram: