Resonant magnetic response of TiO2 microspheres at terahertz frequencies

H. Nemec (1) , C. Kadlec (1) , F. Kadlec (1) , P. Kuzel (1) , Riad Yahiaoui (2) , U-Chan Chung Seu (3, 4) , Catherine Elissalde (3) , Mario Maglione (3) , Patrick Mounaix (2)

1 Institute of Physics
2 LOMA - Laboratoire Ondes et Matière d'Aquitaine
3 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
4 CRPP - Centre de recherches Paul Pascal

Spray-drying technique is used to fabricate spherical microparticles out of dissolved TiO2 nanoparticles. We show both experimentally and through numerical calculations that the microspheres support a Mie resonance, leading to an effective magnetic response. For this purpose, nearly single layers of microspheres were prepared and characterized by time-domain terahertz spectroscopy. We developed an experimental approach allowing simultaneous measurement of complex transmittance and reflectance of a thin layer, which in turn enables evaluation of its effective dielectric permittivity and effective magnetic permeability. Numerical finite-element-method calculations of the electromagnetic response show that the prepared microparticles are suitable for preparing a metamaterial with negative effective magnetic permeability.

Mots clés: Dielectric materials; Emission spectroscopy; Optical metamaterials; Terahertz spectroscopy; Finite-element analysis; Nanoparticle; Light scattering; Electromagnetic interactions; Laser micromachining; Transition metal oxides

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Electromagnétisme

H. Nemec, C. Kadlec, F. Kadlec, P. Kuzel, Riad Yahiaoui, et al.. Resonant magnetic response of TiO2 microspheres at terahertz frequencies. Applied Physics Letters, 2012, 100 (6), pp.061117. ⟨10.1063/1.3683540⟩. ⟨hal-00669368⟩