Subluminal group velocity and dispersion of Laguerre Gauss beams in free space

Nestor D. Bareza; Nathaniel Hermosa

doi:10.1038/srep26842

journal article Open Access May 27, 2016

Subluminal group velocity and dispersion of Laguerre Gauss beams in free space

Nestor D. Bareza Nathaniel Hermosa

Scientific Reports Vol. 6 No. 1 · Springer Science and Business Media LLC

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Abstract

AbstractThat the speed of light in free space c is constant has been a pillar of modern physics since the derivation of Maxwell and in Einstein’s postulate in special relativity. This has been a basic assumption in light’s various applications. However, a physical beam of light has a finite extent such that even in free space it is by nature dispersive. The field confinement changes its wavevector, hence, altering the light’s group velocity vg. Here, we report the subluminal vg and consequently the dispersion in free space of Laguerre-Gauss (LG) beam, a beam known to carry orbital angular momentum. The vg of LG beam, calculated in the paraxial regime, is observed to be inversely proportional to the beam’s divergence θ0, the orbital order ℓ and the radial order p. LG beams of higher orders travel relatively slower than that of lower orders. As a consequence, LG beams of different orders separate in the temporal domain along propagation. This is an added effect to the dispersion due to field confinement. Our results are useful for treating information embedded in LG beams from astronomical sources and/or data transmission in free space.

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References

32

[1]

Giovannini, D. et al. Spatially structured photons that travel in free space slower than the speed of light. Science 347, 857–860 (2015). 10.1126/science.aaa3035

[2]

Alfano, R. R. & Nolan, D. A. Slowing of bessel light beam group velocity. Opt. Commun. 361, 25–27 (2016). 10.1016/j.optcom.2015.10.016

[3]

Mazilu, M. & Dholakia, K. Twisted photons: applications of light with orbital angular momentum (eds Torres, J. P., Torner, L. ) Ch. 4, 37–62 (John Wiley & Sons, 2011). 10.1002/9783527635368.ch4

[4]

Orbital angular momentum of light and the transformation of Laguerre-Gaussian laser modes

L. Allen, M. W. Beijersbergen, R. J. C. Spreeuw et al.

Physical Review A 1992 10.1103/physreva.45.8185

[5]

Curtis, J. E., Koss, B. A. & Grier, D. G. Dynamic holographic optical tweezers. Opt. Commun. 207, 169–175 (2002). 10.1016/s0030-4018(02)01524-9

[6]

Galaja, P. et al. Twisted photons: applications of light with orbital angular momentum (eds Torres, J. P., Torner, L. ) Ch. 7, 117–139 (John Wiley & Sons, 2011). 10.1002/9783527635368.ch7

[7]

Simpson, N., Dholakia, K., Allen, L. & Padgett, M. Mechanical equivalence of spin and orbital angular momentum of light: an optical spanner. Opt. Lett. 22, 52–54 (1997). 10.1364/ol.22.000052

[8]

Free-space information transfer using light beams carrying orbital angular momentum

Graham Gibson, Johannes Courtial, Miles J. Padgett et al.

Optics Express 2004 10.1364/opex.12.005448

[9]

Rosales-Guzmán, C., Hermosa, N., Belmonte, A. & Torres, J. P. Experimental detection of transverse particle movement with structured light. Sci. Rep. 3 (2013). 10.1038/srep02815

[10]

Method for Probing the Orbital Angular Momentum of Optical Vortices in Electromagnetic Waves from Astronomical Objects

Gregorius C. G. Berkhout, Marco W. Beijersbergen

Physical Review Letters 2008 10.1103/physrevlett.101.100801

[11]

Hermosa, N., Aiello, A. & Woerdman, J. Radial mode dependence of optical beam shifts. Opt. Lett. 37, 1044–1046 (2012). 10.1364/ol.37.001044

[12]

Chelkowski, S., Hild, S. & Freise, A. Prospects of higher-order laguerre-gauss modes in future gravitational wave detectors. Phys. Rev. D 79, 122002 (2009). 10.1103/physrevd.79.122002

[13]

Kennedy, S. A., Szabo, M. J., Teslow, H., Porterfield, J. Z. & Abraham, E. Creation of laguerre-gaussian laser modes using diffractive optics. Phys. Rev. A 66, 043801 (2002). 10.1103/physreva.66.043801

[14]

Ryu, C. et al. Observation of persistent flow of a bose-einstein condensate in a toroidal trap. Phys. Rev. Lett. 99, 260401 (2007). 10.1103/physrevlett.99.260401

[15]

Mair, A., Vaziri, A., Weihs, G. & Zeilinger, A. Entanglement of the orbital angular momentum states of photons. Nature 412, 313–316 (2001). 10.1038/35085529

[16]

D’Ambrosio, V., Nagali, E., Marrucci, L. & Sciarrino, F. Orbital angular momentum for quantum information processing. In SPIE Photonics Europe, 84400F–84400F (International Society for Optics and Photonics, 2012). 10.1117/12.924842

[17]

Molina-Terriza, G., Torres, J. P. & Torner, L. Twisted photons. Nat. Phys. 3, 305–310 (2007). 10.1038/nphys607

[18]

Karimi, E. et al. Exploring the quantum nature of the radial degree of freedom of a photon via hong-ou-mandel interference. Phys. Rev. A 89, 013829 (2014). 10.1103/physreva.89.013829

[19]

Djordjevic, I. B. Deep-space and near-earth optical communications by coded orbital angular momentum (oam) modulation. Opt. Express 19, 14277–14289 (2011). 10.1364/oe.19.014277

[20]

Verdeyen, J. T. Laser electronics (Englewood Cliffs, NJ, Prentice Hall, 1989).

[21]

Wang, J. et al. Terabit free-space data transmission employing orbital angular momentum multiplexing. Nat. Photonics 6, 488–496 (2012). 10.1038/nphoton.2012.138

[22]

Karimi, E., Marrucci, L., de Lisio, C. & Santamato, E. Time-division multiplexing of the orbital angular momentum of light. Opt. Lett. 37, 127–129 (2012). 10.1364/ol.37.000127

[23]

Tamburini, F. et al. Encoding many channels on the same frequency through radio vorticity: first experimental test. New J. Phys. 14, 033001 (2012). 10.1088/1367-2630/14/3/033001

[24]

Steinlechner, F., Hermosa, N., Pruneri, V. & Torres, J. P. Frequency conversion of structured light. Sci. Rep. 6, 21390 (2016). 10.1038/srep21390

[25]

Boyd, R. W. Nonlinear optics (Academic press, 2003).

[26]

Efficient measurement of an optical orbital-angular-momentum spectrum comprising more than 50 states

Martin P J Lavery, David J Robertson, Anna Sponselli et al.

New Journal of Physics 2013 10.1088/1367-2630/15/1/013024

[27]

Padgett, M. J., Miatto, F. M., Lavery, M. P., Zeilinger, A. & Boyd, R. W. Divergence of an orbital-angular-momentum-carrying beam upon propagation. New J. Phys. 17, 023011 (2015). 10.1088/1367-2630/17/2/023011

[28]

Yang, Y. et al. Effect of the radial and azimuthal mode indices of a partially coherent vortex field upon a spatial correlation singularity. New J. Phys. 15, 113053 (2013). 10.1088/1367-2630/15/11/113053

[29]

Yang, Y. & Liu, Y.-d. Measuring azimuthal and radial mode indices of a partially coherent vortex field. J. Opt. 18, 015604 (2015). 10.1088/2040-8978/18/1/015604

[30]

Hickmann, J., Fonseca, E., Soares, W. & Chávez-Cerda, S. Unveiling a truncated optical lattice associated with a triangular aperture using light’s orbital angular momentum. Phys. Rev. Lett. 105, 053904 (2010). 10.1103/physrevlett.105.053904

[31]

Guo, C.-S., Lu, L.-L. & Wang, H.-T. Characterizing topological charge of optical vortices by using an annular aperture. Opt. Lett. 34, 3686–3688 (2009). 10.1364/ol.34.003686

[32]

Griffiths, D. J. & College, R. Introduction to electrodynamics vol. 3 (prentice Hall Upper Saddle River, NJ, 1999).

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Published: May 27, 2016
Vol/Issue: 6(1)
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Cite This Article

Nestor D. Bareza, Nathaniel Hermosa (2016). Subluminal group velocity and dispersion of Laguerre Gauss beams in free space. Scientific Reports, 6(1). https://doi.org/10.1038/srep26842

Subluminal group velocity and dispersion of Laguerre Gauss beams in free space

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