- Radial polarisation
A beam of light has radial polarisation if at every position in the beam the
polarisation (electric field ) vector points towards the centre of the beam. In practice, an array ofwaveplate s may be used to provide an approximation to a radially polarised beam. In this case the beam is divided into segments (eight, for example), and the average polarisation vector of each segment is directed towards the beam centre.cite journal |title=z-Polarization sensitive detection in micro-Raman spectroscopy by radially polarized incident light |first=Y. |last=Saito |coauthors=Kobayashi, M.; Hiraga, D.; Fujita, K.; Kawano, S.; Smith, N. I.; Inouye, Y.; Kawata, S. |journal=Journal of Raman Spectroscopy |month=Mar |year=2008 |doi=10.1002/jrs.1953] It is possible to use aliquid crystal device to convert the polarisation of a beam to a radial state,cite web |url=http://www.arcoptix.com/radial_polarization_converter.htm |title=Radial-Azimuthal Polarization Converter |accessdate=2008-09-30] or a radially polarised beam can be produced by alaser in which theBrewster window is replaced by a cone atBrewster's angle .cite journal |title=Generation of a radially polarized laser beam by use of a conical Brewster prism |first=Yuichi |last=Kozawa |coauthors= Sato, Shunichi |journal=Optics Letters |volume=30 |issue=22 |pages=3063–3065 |doi=10.1364/OL.30.003063 |year=2005]A radially polarised beam can be used to produce a smaller focused spot than a more conventional linearly or circularly polarised beamcitation |title=Radial polarization minimizes focal spot size |last=Quabis |first=S. |coauthors=Dorn, R.; Muller, J.; Rurimo, G.K.; Leuchs, G. |journal=Quantum Electronics Conference 2004 (IQEC) |pages=615–616| doi=10.1109/IQEC.2004.242867 |isbn=1-55752-778-4 |doi_brokendate=2008-10-03] , and has uses in optical trapping.cite journal |title=Trapping metallic Rayleigh particles with radial polarization, |author=Qiwen Zhan |journal=Optics Express |volume=12 |issue=15 |pages=3377–3382 |doi=10.1364/OPEX.12.003377 |year=2004]
ee Also
*
Polarization
*Axial polarisation
*Longitudinal polarisation References
Wikimedia Foundation. 2010.
