We theoretically examine the bending loss of organic molecular-crystal nanofibers for which the light propagation is carried out by optically anisotropic exciton polaritons. Previous experimental studies showed that the leakage of light for bent thiacyanine nanofibers was negligibly small even for the radius of curvature of several microns. We formulate a finite-difference frequency-domain method stabilized by a conformal transformation to calculate the bending loss as a function of the radius of curvature and the propagation frequency. The present method is applied to the thiacyanine nanofiber and numerical results that support the previous experimental observation are obtained. The present study clearly shows that the polariton nanofiber gives a novel possibility for bent waveguides to fabricate optical microcircuits and interconnection that cannot be attained by the conventional waveguides based on the index guiding.
© 2013 Optical Society of America
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