  Babinet complementary patterns of a spectrally tunable metamaterial
incorporating a nematic liquid crystal are normally assumed to exhibit the same
tuning range. Here we show that for a hybrid, terahertz liquid
crystal-metamaterial, the sensitivity of its resonances to the variations of
the refractive index differs substantially for the two complementary patterns.
This is due to a mismatch between the alignment of the liquid crystal and the
direction of the local electric field induced in the patterns. Furthermore, and
more intriguingly, our experimental data indicate that it is possible to shift
the resonance of the positive metamaterial pattern beyond the limit imposed by
the alignment mismatch. Our analysis suggests that the observed anomalous
frequency shift result from the orientational optical nonlinearity of a nematic
liquid crystal.
