Ian RM O'Reilly
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SAM to OAM Conversion Applications
Overview
~Patent for light rectification using an optical vortex
~An optical vortex is a beam that has some non-uniform structure to the wave front that rotates temporally
~Optical vortices are created by passing circularly polarized light with spin angular momentum through an q-Waveplate
~ Optical Vortices have orbital angular momentum that can be transferred to micro-particles to induce a circular orbit.
Linear Polarization
Circular Polarization
Quarter Waveplate
The Optical Vortex
~ "L" is OAM Quantum Number
~Left: Wavefront With Poynting Vector
~Center: Anular Intensity Profile
~Right: Interference With Plane Wave
Q-Plate
q = 1 plate
~Patterned sub-wavelength grating produced by nanosecond laser etching
~q parameter defines
number of rotations in grating
~Orientation of incident light with grating produces birefringence
~ Converts Circular Polarization to Optical Vortex
SAM to OAM
±ℏ SAM per photon
ΔL = ±2q
OAM = L ℏ
Effect On Paticles
Particle Orbit
Spheroid Particle Rotation
S-Waveplate Transmission
Our Calculation
- ℏ = 1.05 E -34 J S
- Sunlight is Roughly 1000 W/m^2 and averages to 500 nm
- E = h*c*f
- Which Yields 2.515 E 21 Photons/m*s
Our Calculation
- Assuming Each Photon Transfers ℏ AM to an electron
- L = r X M * V
- V = 11.53 m/s
- Ignoring The Drude Model
- KE = 1/2 M * V^2
- KE = 1.5 E -7 J/S
Image References and Useful Papers
Beresna, Martynas, Mindaugas Gecevičius, and Peter G. Kazansky. "Polarization Sensitive Elements Fabricated by Femtosecond Laser Nanostructuring of Glass [Invited]." Optical Materials Express Opt. Mater. Express 1.4 (2011): 783. Web.
Gecevičius, Mindaugas, Rokas Drevinskas, Martynas Beresna, and Peter G. Kazansky. "Single Beam Optical Vortex Tweezers with Tunable Orbital Angular Momentum." Applied Physics Letters Appl. Phys. Lett. 104.23 (2014): 231110. Web.
Marrucci, Lorenzo, Ebrahim Karimi, Sergei Slussarenko, Bruno Piccirillo, Enrico Santamato, Eleonora Nagali, and Fabio Sciarrino. "Spin-to-orbital Conversion of the Angular Momentum of Light and Its Classical and Quantum Applications." Journal of Optics J. Opt. 13.6 (2011): 064001. Web.
Padgett, Miles, Johannes Courtial, and Les Allen. "Lights Orbital Angular Momentum." Physics Today. N.p., n.d. Web.
Piccirillo, Bruno, and Enrico Santamato. "Light Angular Momentum Flux and Forces in Birefringent Inhomogeneous Media." Physical Review E Phys. Rev. E 69.5 (2004): n. pag. Web.
Zhu, Lie, Zhongyi Guo, Qiang Xu, Jingran Zhang, Anjun Zhang, Wei Wang, Yi Liu, Yan Li, Xinshun Wang, and Shiliang Qu. "Calculating the Torque of the Optical Vortex Tweezer to the Ellipsoidal Micro-particles." Optics Communications 354 (2015): 34-39.
Image References and Useful Papers Cont.
Haines, M. G. "Generation of an Axial Magnetic Field from Photon Spin." Phys. Rev. Lett. Physical Review Letters 87.13 (2001): n. pag. Web.
Zhang, Hui-Liang, Yan-Zhong Wang, and Xiang-Jun Chen. "A Simple Explanation for the Inverse Faraday Effect in Metals." Journal of Magnetism and Magnetic Materials 321.24 (2009): n. pag. Web.
SAM to OAM
By Ian RM O'Reilly
