  Quantum coherence in atomic systems has led to fascinating outcomes, such as
laser cooling and trapping, Bose-Einstein condensates, and
electromagnetically-induced-transparency (EIT). In EIT, the sharp cancellation
of medium absorption has led to phenomena such as lasing without inversion,
freezing light, and dynamic storage of light in a solid-state system. Similar
to atomic systems, EIT-like effects can be observed through classical and
optical means. Here we report the first experimental deterministic tuning of
all-optical analogue to EIT in coherently-coupled standing-wave photonic
crystal cavities. Our observations include transparency-resonance lifetimes
more than three times the single loaded cavity, Fano-type lineshapes, and
stepwise control of the coherent cavity-cavity interference. Our system, with
wavelength-scale localization and coupled to a single waveguide, is analyzed
well through the coupled-mode formalism which examines the delay in both
transparency- and Fano-like lineshapes. Our observations support applications
towards all-optical trapping, stopping and time-reversal of light in a
solid-state scalable implementation.
