Thermo-optically induced transparency on a photonic chip

Controlling the optical response of a medium through suitably tuned coherent electromagnetic fields is highly relevant in a number of potential applications,from all-optical modulators to optical storage devices.In particular,electromagnetically induced transparency(EIT)is an established phenomenon in which destructive quantum interference creates a transparency window over a narrow spectral range around an absorption line,which,in turn,allows to slow and ultimately stop light due to the anomalous refractive index dispersion.Here we report on the observation of a new form of both induced transparency and amplification of a weak probe beam in a strongly driven silicon photonic crystal resonator at room temperature.The effect is based on the oscillating temperature field induced in a nonlinear optical cavity,and it reproduces many of the key features of EIT while being independent of either atomic or mechanical resonances.Such thermo-optically induced transparency will allow a versatile implementation of EIT-analogs in an integrated photonic platform,at almost arbitrary wavelength of interest,room temperature and in a practical,low cost,and scalable system.