This paper was published in Applied Optics and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website:
http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-31-33-6979Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.
Page published on the 10th of November, 2009
Last updated on the 16th of February, 2015