  We investigate the electromagnetic response of asymmetric broadside coupled
split ring resonators (ABC-SRRs) as a function of the relative in-plane
displacement between the two component SRRs. The asymmetry is defined as the
difference in the capacitive gap widths (\Delta g) between the two resonators
comprising a coupled unit. We characterize the response of ABC-SRRs both
numerically and experimentally via terahertz time-domain spectroscopy. As with
symmetric BC-SRRs (\Delta g=0 \mu m), a large redshift in the LC resonance is
observed with increasing displacement, resulting from changes in the capacitive
and inductive coupling. However, for ABC-SRRs, in-plane shifting between the
two resonators by more than 0.375Lo (Lo=SRR sidelength) results in a transition
to a response with two resonant modes, associated with decoupling in the
ABC-SRRs. For increasing \Delta g, the decoupling transition begins at the same
relative shift (0.375Lo), though with an increase in the oscillator strength of
the new mode. This strongly contrasts with symmetric BC-SRRs which present only
one resonance for shifts up to 0.75Lo. Since all BC-SRRs are effectively
asymmetric when placed on a substrate, an understanding of ABC-SRR behavior is
essential for a complete understanding of BC-SRR based metamaterials.
