Excitation of the radiationless anapole mode

The existence of non-radiating sources is of fundamental importance for inverse scattering problems and the design of invisible objects. However, the excitation of such radiationless sources is quite challenging. We present a method based on which the anapole mode of a high-index isotropic dielectric nanosphere can be excited but radiationless. We show that this radiationless anapole is attributed to the destructive interference of the Cartesian dipole and toroidal moment of the induced current by our proposed focused radially polarized beam illumination. Further, with a standing-wave illumination formed by two counter-propagating focused radially polarized beams under 4π configuration, the ideal radiationless anapole can be excited. This result illustrates a case where the reciprocity condition is not violated, and yet, a radiationless mode can be excited by external illumination.

[1]  Bernhard J. Hoenders,et al.  Existence of invisible nonscattering objects and nonradiating sources , 1997 .

[2]  Andrey E. Miroshnichenko,et al.  Magnetic light , 2012, Scientific reports.

[3]  C. Sheppard,et al.  Multipole theory for tight focusing of polarized light, including radially polarized and other special cases. , 2012, Journal of the Optical Society of America. A, Optics, image science, and vision.

[4]  Mário G. Silveirinha,et al.  Optical meta-atom for localization of light with quantized energy , 2015, Nature Communications.

[5]  H. Urbach,et al.  Broadband active tuning of unidirectional scattering from nanoantenna using combined radially and azimuthally polarized beams. , 2015, Optics letters.

[6]  E. Wolf,et al.  Electromagnetic diffraction in optical systems, II. Structure of the image field in an aplanatic system , 1959, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[7]  V. M. Dubovik,et al.  Toroid moments in electrodynamics and solid-state physics , 1990 .

[8]  U. Leonhardt.  Optical Conformal Mapping , 2006, Science.

[9]  A. J. Devaney,et al.  Radiating and nonradiating classical current distributions and the fields they generate , 1973 .

[10]  M. Silveirinha.  Trapping light in open plasmonic nanostructures , 2014 .

[11]  B. Chichkov,et al.  Demonstration of magnetic dipole resonances of dielectric nanospheres in the visible region. , 2012, Nano letters.

[12]  D. P. Tsai,et al.  Non-Trivial Non-Radiating Excitation as a Mechanism of Resonant Transparency in Toroidal Metamaterials , 2012, 1211.3840.

[13]  C. Sheppard,et al.  Interpretation of the scattering mechanism for particles in a focused beam , 2012 .

[14]  D. P. Tsai,et al.  Toroidal Dipolar Response in a Metamaterial , 2010, Science.

[15]  G. N. Afanasiev,et al.  THE ELECTROMAGNETIC FIELD OF ELEMENTARY TIME-DEPENDENT TOROIDAL SOURCES , 1995 .

[16]  D. P. Tsai,et al.  Resonant Transparency and Non-Trivial Non-Radiating Excitations in Toroidal Metamaterials , 2013, Scientific Reports.

[17]  Tarek M. Habashy,et al.  Invisible Bodies and Uniqueness of the Inverse Scattering Problem , 1993 .

[18]  H Paul Urbach,et al.  Finite-element model for three-dimensional optical scattering problems. , 2007, Journal of the Optical Society of America. A, Optics, image science, and vision.

[19]  R. Scherrer,et al.  Anapole dark matter , 2012, 1211.0503.

[20]  Boris N. Chichkov,et al.  Nonradiating anapole modes in dielectric nanoparticles , 2015, Nature Communications.

[21]  G. Goedecke.  Classically Radiationless Motions and Possible Implications for Quantum Theory , 1964 .

[22]  G. A. Schott.  LIX.The electromagnetic field of a moving uniformly and rigidly electrified sphere and its radiationless orbits , 1933 .

[23]  Kisik Kim,et al.  Non-radiating monochromatic sources and their fields , 1986 .