  We experimentally demonstrate at terahertz frequencies that a planar
metamaterial exhibits a spectral response resembling electromagnetically
induced transparency. The metamaterial unit cell consists of a split ring
surrounded by another closed ring where their dimensions are such that their
excitable lowest order modes have identical resonance frequencies but very
different life times. Terahertz time-domain spectroscopy verifies that the
interference of these two resonances results in a narrow transparency window
located within a broad opaque region. In contrast to previous studies this
enhanced transmission is achieved by independently exciting two resonances in
which their coupling to the radiation field, and thus their linewidth, differs
strongly. Rigorous numerical simulations prove that the transparency window is
associated with a large group index and low losses, making the design
potentially useful for slow light applications. This experiment opens an avenue
to explore quantum mechanical phenomena using localized resonances in metallic
structures,
