Highly efficient excitation of optical near-field on an apertured fiber probe with an asymmetric structure

Abstract

We propose and demonstrate a novel method to enhance the near-field optical intensity on the apertured probe with its foot removed asymmetrically by using a focused ion beam. The spatial distribution of the near-field optical intensity on the asymmetric probe was observed by scanning another sharpened symmetric probe over the aperture. The observed spatial distribution profile was in good agreement with a numerical result corresponding to the HE11 mode. Furthermore, compared with the symmetric apertured probe, a 10 times enhancement of the near-field optical intensity on the asymmetric apertured probe was observed.