Spin and orbital angular momenta of light reflected from a cone
- College of Optical Sciences, University of Arizona, Tucson, Arizona 85721 (United States)
- Corning Incorporated, Science and Technology Division, Corning, New York 14831 (United States)
We examine several retro-reflecting optical elements, each involving two reflections. In the case of a hollow metallic cone having an apex angle of 90 deg., a circularly polarized incident beam acquires, upon reflection, the opposite spin angular momentum. However, no angular momentum is transferred to the cone, because the reflected beam picks up an orbital angular momentum that is twice as large but opposite in direction to that of its spin. A 90 deg. cone made of a transparent material in which the incident light suffers two total internal reflections before returning may be designed to endow the retro-reflected beam with different mixtures of orbital and spin angular momenta. Under no circumstances, however, is it possible to transfer angular momentum from the light beam to the cone without either allowing absorption or breaking the axial symmetry of the cone. A simple example of broken symmetry is provided by a wedge-shaped metallic reflector having an apex angle of 90 deg., which picks up angular momentum upon reflecting a circularly polarized incident beam.
- OSTI ID:
- 22072179
- Journal Information:
- Physical Review. A, Vol. 84, Issue 3; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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