Electromagnetically induced transparency and wideband wavelength conversion in silicon nitride microdisk optomechanical resonators
Yuxiang Liu, Marcelo Davanco, Vladimir Aksyuk, and Kartik Srinivasan
Accepted
We demonstrate optomechanically-mediated electromagnetically-induced transparency and wavelength conversion in silicon nitride (Si$_3$N$_4$) microdisk resonators. Fabricated devices support whispering gallery optical modes with a quality factor ($Q$) of 10$^6$, and radial breathing mechanical modes with a $Q$=10$^4$ and a resonance frequency of 625~MHz, so that the system is in the resolved sideband regime. Placing a strong optical control field on the red (blue) detuned sideband of the optical mode produces coherent interference with a resonant probe beam, inducing a transparency (absorption) window for the probe. This is observed for multiple optical modes of the device, all of which couple to the same mechanical mode, and which can be widely separated in wavelength due to the large bandgap of Si$_3$N$_4$. These properties are exploited to demonstrate frequency upconversion and downconversion of optical signals between the 1300 nm and 980 nm bands.