Thermo-Optically Induced Transparency on a photonic chip

Abstract

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 1

Electromagnetically induced transparency from first-order dynamical systems

“…We note that, while the first experimental evidences for thermo-optically induced transparency have already been reported [18,19], the free-carrier induced transparency phenomenon predicted here is a novel effect. While this work aims at providing a theoretical framework for the formulation and interpretation of a novel phenomenon, our purpose is also to introduce the key analytic tools to design the practical implementation of large group delays and advances in actual photonic devices based on conventional material platforms, thus fostering new experiments allowing to leverage the stringent requirements of typical EIT-analogue physics.…”

“…This value is, in general, larger for smaller sized microcavities, as highlighted by recent experiments. In particular, a linewidth in the sub-MHz range has been reported in the case of TOIT measured in an integrated silicon PhC cavity [18], and a sensibly slower dynamics in the case of a bulk Fabry-Pérot system, with a linewidth of the order of 100 Hz [19]. Indeed, typical orders of magnitude for integrated resonators are in the range γ/2π ∼ 1 MHz for both silicon PhC cavities [28,31] and microring resonators [32,33], respectively.…”

“…While thermal bistability is a well-known phenomenon in the domain of optical microcavites [21,28], thermooptically induced transparency (TOIT) has been demonstrated only very recently [18,19], and it can be regarded as a peculiar example of induced transparency from a first-order dynamical system obtained through mechanisms discussed in the previous Section. Within this context, the previously introduced characteristic bistability energy is given by:…”

“…Nevertheless, this nonlinearity has already been explored in the past for applications such as low-power all-optical switching [30]. In the framework of TOIT, this translates in a very low threshold for the activation of the observed phenomenology [18].…”

“…In contrast, the expressions for the phase and the group delay become more complicated in this case than the ones introduced in Eqs. (18) and Eq. ( 20), respectively.…”