Abstract
We demonstrate the realization of a new hybrid magnetoplasmonic thin film structure that resembles the classical optical analog of electromagnetically induced absorption. In transmission geometry our gold nanostructure embedded in an EuS film induces giant Faraday rotation of over 14° for a thickness of less than 200 nm and a magnetic field of 5 T at . By varying the magnetic field from to , a rotation tuning range of over 25° is realized. As we are only a factor of 3 away from the Faraday isolation requirement, our concept could lead to highly integrated, nonreciprocal photonic devices for light modulation, optical isolation, and optical magnetic field sensing.
- Received 6 February 2017
DOI:https://doi.org/10.1103/PhysRevX.7.021048
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
Published by the American Physical Society
Physics Subject Headings (PhySH)
Popular Summary
Many modern optical technologies, such as lasers and high-speed data communication, depend on nonreciprocal optical devices, which behave differently for forward and backward traveling light waves. The most important example is optical isolators, which are transparent for forward-propagating light but block light that propagates backward. This prevents, for example, damage to laser diodes upon back reflection. Usually, nonreciprocal devices rely on the Faraday effect, where the polarization of light traveling through a material is rotated depending on the direction of an applied magnetic field. The growing demand for highly miniaturized devices, however, is challenging for Faraday rotators, which typically require large crystals of roughly centimeter size. By modifying a thin film, we show a way that much smaller Faraday rotators could be built.
We use a thin film of europium sulfide (EuS) to demonstrate that the Faraday effect can be substantially enhanced by the inclusion of gold nanoscale metal wire arrays. With the application of an external magnetic field, we measure a Faraday rotation of light of 14 ° transmitted through the film. Varying the magnetic field lets us change the rotation over a range of 25 °. Although our structures are less than 200 nm thick, their performance is only a factor of 3 smaller than centimeter-sized Faraday rotators used in conventional optical isolators.
Modifications to our design could result in a Faraday rotation close to or above 45 °. Hence, our concept could pave the way to novel applications in laser and communication systems.