We present fabrication, characterization, and simulation results on an optical antenna inspired by the Sierpinski carpet fractal geometry for operation in the visible and near-infrared wavelength regions. Measurements and simulations of the far-field scattering efficiency indicate a broadband optical response. Two-photon photoluminescence images provide maps of the near-field intensity distribution, from which we extract an enhancement factor of ~70. To explore the effect of morphology on the optical response of a large assembly of particles, we also present results on an arbitrarily chosen pseudo-random configuration as well as a periodic array.
Chen, T. L., Dikken, D. J., Prangsma, J. C., Segerink, F., & Herek, J. L. (2014). Characterization of Sierpinski carpet optical antenna at visible and near-infrared wavelengths. New journal of physics, 16, . https://doi.org/10.1088/1367-2630/16/9/093024