锥形镀膜光纤探针近场分布特性

采用三维时域有限差分法对锥形镀膜光纤探针的近场分布特性进行了研究，结果表明入射光照射到探针上出现了退极化现象，光纤探针的近场分布不具有圆周对称性，探针的纵向截面中，与入射偏振光垂直的截面和与入射偏振光平行的截面两者的近场分布差异较大．在其它光纤探针参量相同的情况下对不同锥角的光纤探针进行了计算和比较，结果表明锥角越大从探针尖端出射的光强越大，从光波波导的角度对这种现象进行了分析。

THE NEAR- FIELD PROPERTIES OF THE METAl-COATED FIBER PROBE

The near-field distributions of tapered metal-coated optical fiber probe are characterized based on the 3D finite-difference time-domain(FDTD).The calculation result reveals that the polarized incident light becomes(depolarized) after emitting from the small aperture of the probe.The near-field distributions of the probe are(unsymmetrical),and the near-field distributions of the cross section vertical to the polarized wave are different from that of the(cross) section parallel to the polarized wave.The relationship between the(electric-field magnitude) and the taper(angle) is(calculated),keeping other parameters unalterable.It reveals that the larger the taper angle is,the greater the(electric-field) magnitude is.We analyze this phenomenon in terms of the light waveguide.