Abstract-Enhanced spin-precession dynamics in a spin-metamaterial coupled resonator observed in terahertz time-domain measurements

T. Kurihara, K. Nakamura, K. Yamaguchi, Y. Sekine, Y. Saito, M. Nakajima, K. Oto, H. Watanabe, and T. Suemoto

https://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.144408

We demonstrate enhancement of the spin precession of orthoferrite ErFeO3 using the magnetic near-field produced by a split-ring resonator (SRR), using the terahertz pump-optical Faraday probe measurement. The precession amplitude was enhanced by ∼8 times when the resonance frequency of spin precession was close to the magnetic resonance of SRR. The time evolution of spin precession was successfully reproduced by a coupled spin- and SRR-resonance model mediated by the magnetic near-field. It is suggested that optimization of the metamaterial structure would further increase the enhancement factor, leading to the nonlinear control of spin dynamics using terahertz radiation.

DOI: http://dx.doi.org/10.1103/PhysRevB.90.144408

• 
• 
• 
• 

• 
  

Abstract-Dielectric probe for scattering-type terahertz scanning near-field optical microscopy

T. Kurihara¹, K. Yamaguchi¹, H. Watanabe¹, M. Nakajima², and T. Suemoto¹

¹Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8581, Japan
²Department of Physics, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan

http://apl.aip.org/resource/1/applab/v103/i15/p151105_s1?isAuthorized=no

Dielectric material was used as the probe material for a scattering-type terahertz scanning near-field optical microscope (THz S-SNOM). It was found that the dielectric probe exhibits a strong near-field scattering signal with an amplitude comparable to that of the metallic probe. The behavior of the electric near-field around the tip was calculated using the finite-difference time-domain method, showing the field enhancement comparable to that of the metallic probe. The dielectric probe also exhibited a faster temporal response compared to the response of the metallic probe. Introduction of a non-metallic probe would enlarge the application field of the THz S-SNOM technique.

© 2013 AIP Publishing LLC