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 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.
Highlights
Induced transparency (EIT) is a coherent phenomenon in which a control laser induces transparency for a weaker probe laser in an otherwise opaque medium[1]
This is associated with an amplification rate of 4.4 dB μs−1, a result in stark contrast with other integrated photonic devices, where delay is typically associated with losses in the dB ns−1 range[23]
In ref. 21 we present a numerical model for the accurate description of the thermo-optic response of a cavity such as the one studied here under a constant pump scenario and show that structuring of the surrounding medium can engineer the heat flow out of the cavity
Summary
Induced transparency (EIT) is a coherent phenomenon in which a control laser induces transparency for a weaker probe laser in an otherwise opaque (or optically thick) medium[1]. EIT experiments typically require complicated set-up configurations and very low operating temperature, driving research into related and analogous effects such as coherent population oscillations (CPO)[5], coupledresonator structures[6], Brillouin-scattering induced transparency (BSIT)[7,8] and opto-mechanically induced require structures that support acoustic or mechanical modes. While these approaches can achieve large delays (μs) this comes at the cost of complex structures and device design. We show a novel and general nonlinear phenomenon, based on the thermo-optic effect, displaying both induced transparency and amplification of a weak probe beam coherently coupled to a strong control field[13].
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