Photon self-induced spin-to-orbital conversion in a terbium-gallium-garnet crystal at high laser power

Journal Article · Fri Oct 15 00:00:00 EDT 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.82.043806· OSTI ID:21464474

Mosca, S; De Rosa, R; Milano, L ^[1]; Canuel, B; Genin, E ^[2]; Karimi, E ^[1]; Piccirillo, B; Santamato, E ^[1]; Marrucci, L ^[1]

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1. Dipartimento di Scienze Fisiche, Universita di Napoli 'Federico II', Complesso Universitario di Monte S. Angelo, 80126 Napoli (Italy)
2. EGO, European Gravitational Observatory, Via E. Amaldi, 56021 S. Stefano a Macerata, Cascina (Italy)

In this paper, we present experimental evidence of a third-order nonlinear optical process, self-induced spin-to-orbital conversion (SISTOC) of the photon angular momentum. This effect is the physical mechanism at the origin of the depolarization of very intense laser beams propagating in isotropic materials. The SISTOC process, like self-focusing, is triggered by laser heating leading to a radial temperature gradient in the medium. In this work we tested the occurrence of SISTOC in a terbium-gallium-garnet rod for an impinging laser power of about 100 W. To study the SISTOC process we used different techniques: polarization analysis, interferometry, and tomography of the photon orbital angular momentum. Our results confirm, in particular, that the apparent depolarization of the beam is due to the occurrence of maximal entanglement between the spin and orbital angular momentum of the photons undergoing the SISTOC process. This explanation of the true nature of the depolarization mechanism could be of some help in finding novel methods to reduce or to compensate for this usually unwanted depolarization effect in all cases where very high laser power and good beam quality are required.

• OSTI ID: 21464474
• Journal Information: Physical Review. A, Vol. 82, Issue 4; Other Information: DOI: 10.1103/PhysRevA.82.043806; (c) 2010 The American Physical Society; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CONVERSION
CRYSTALS
DEPOLARIZATION
FOCUSING
GALLIUM COMPOUNDS
GARNETS
INTERFEROMETRY
LASER RADIATION
LASER-RADIATION HEATING
NONLINEAR PROBLEMS
ORBITAL ANGULAR MOMENTUM
PHOTON BEAMS
PHOTONS
POLARIZATION
RODS
SPIN
TEMPERATURE GRADIENTS
TERBIUM COMPOUNDS
ANGULAR MOMENTUM
BEAMS
BOSONS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
HEATING
MASSLESS PARTICLES
MINERALS
PARTICLE PROPERTIES
PLASMA HEATING
RADIATIONS
RARE EARTH COMPOUNDS
SILICATE MINERALS