Near-field second-harmonic microscopy of thin ferroelectric films

2019-11-09 03:31:17

harmonic optical field ferroelectric SH

责任者: Smolyaninov, I.I.;Liang, H.Y.;Lee, C.H.;Davis, C.C.;Aggarwal, S.;Ramesh, R. 单位: Dept. of Electr. & Comput. Eng., Maryland Univ., College Park, MD, USA 来源出处: Optics Letters(Opt. Lett. (USA)),2000/06/01,25(11):835-7 摘要: We present a near-field optical technique for second-harmonic imaging by use of tapered optical fiber tips externally illuminated with femtosecond laser pulses. Enhancement of the electric field at the tip of the fiber results in enhanced second-harmonic (SH) generation from the sample region near the tip. This SH emission is collected by the same tapered fiber. The spatial distribution and polarization properties of SH generation from thin ferroelectric films and a poled single crystal of BaTiO3 have been studied. A spatial resolution of the order of 80 nm was achieved. Symmetry properties of the near-field SH signal allow us to recover the local poling direction of individual ferroelectric domains in the film. Thus the technique provides a novel tool for nanometer-scale crystal analysis of polycrystalline samples 关键词: barium compounds;dielectric polarisation;electric domains;electric fields;ferroelectric thin films;image resolution;light polarisation;optical fibres;optical harmonic generation;optical microscopy;near-field second-harmonic microscopy;thin ferroelectric films;near-field optical technique;second-harmonic imaging;tapered optical fiber tips;femtosecond laser pulses;external illumination;electric field enhancement;enhanced SHG;sample region;SH emission;spatial distribution;polarization properties;BaTiO3 poled single crystal;spatial resolution;symmetry properties;near-field SH signal;local poling direction;ferroelectric domains;nanometer-scale crystal analysis;polycrystalline samples;BaTiO3