A route toward lineshape engineering of Fano resonances in photonic
structures is theoretically proposed, which uses dynamic modulation of the
refractive index of a microcavity. The method is exemplified by considering
coupled-resonator optical waveguide systems. An exact Floquet analysis, based
on coupled-mode theory, is presented. Two distinct kinds of resonances can be
dynamically created, depending on whether the static structure sustains a
localized mode or not. In the former case a single Fano resonance arises, which
can be tuned in both frequency and line width by varying the refractive index
modulation amplitude and frequency. In the latter case two resonances, in the
form of narrow asymmetric dips in the transmittance, are found, which can
overlap resulting in an electromagnetically-induced transparency effect.Comment: 4 figures, 6 pages, to be published in Phys. Rev.
