Ultrafast All-Optical Switching with Magnetic Resonances in Nonlinear Dielectric Nanostructures

• Published in: Nano letters Vol. 15; no. 10; pp. 6985 - 6990
• Main Authors: Shcherbakov, Maxim R, Vabishchevich, Polina P, Shorokhov, Alexander S, Chong, Katie E, Choi, Duk-Yong, Staude, Isabelle, Miroshnichenko, Andrey E, Neshev, Dragomir N, Fedyanin, Andrey A, Kivshar, Yuri S
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 14.10.2015
• Subjects: Dielectrics; Femtosecond; Magnetic resonance; Magnetics; Nanostructure; Nanostructures; Nonlinear optics; Nonlinearity; Photons; Spectra; Switching; femtosecond optics; all-optical switching; optical magnetism; silicon photonics; Nonlinear optics; metasurfaces
• ISSN: 1530-6984; 1530-6992; 1530-6992
• DOI: 10.1021/acs.nanolett.5b02989

We demonstrate experimentally ultrafast all-optical switching in subwavelength nonlinear dielectric nanostructures exhibiting localized magnetic Mie resonances. We employ amorphous silicon nanodisks to achieve strong self-modulation of femtosecond pulses with a depth of 60% at picojoule-per-disk pump energies. In the pump–probe measurements, we reveal that switching in the nanodisks can be governed by pulse-limited 65 fs-long two-photon absorption being enhanced by a factor of 80 with respect to the unstructured silicon film. We also show that undesirable free-carrier effects can be suppressed by a proper spectral positioning of the magnetic resonance, making such a structure the fastest all-optical switch operating at the nanoscale.