Beyond-limit light focusing in the intermediate zone

Chen, K. R.; Chu, W. H.; Fang, H. C.; Liu, C. P.; Huang, C. H.; Chui, H. C.; Chuang, C. H.; Lo, Y. L.; Lin, C. Y.; Chang, S. J.; Hung, F. Y.; Hwuang, H. H.; Fuh, Andy Y. -G.

Beyond-limit light focusing in the intermediate zone

Authors

Description

We experimentally demonstrate that a new nanolens of designed plasmonic subwavelength aperture can focus light to a single-line with its width beyond the diffraction limit that sets the smallest achievable line width at half the wavelength. The measurements indicate that the effect of the near-field on the light focused is negligible in the intermediate zone of 2 < kr < 4 where the line-width is smaller than the limit. Thus, as a verification of theoretical prediction, the fields focused are radiative and with a momentum capable of propagating to the far zone as concerned by the limit.
16 pages, 4 figures