Ultrafast optical phenomena in magneto-plasmonic crystals and magnetically ordered materials

Abstract

The understanding and control of fundamental light-matter interactions is able to provide solutions for current challenges concerning light-emitting diodes, solar-cells, microchip design, data storage and many more. Driven by the need of compact, fast and energy efficient device technologies, ultrafast optical phenomena are studied in different material systems by means of femtosecond time-resolved pump-probe techniques. The presented experiments focus on magneto-optic phenomena as a tool for external optical control. By means of femtosecond laser pulses, these are observed on timescales comparable to the exchange interaction or typical electron scattering times, which grants deep insight into the electronic processes involved. The aim is to gain fundamental knowledge for the optical control of the material’s magneto-optical properties for all-optical applications. In magneto-plasmonic crystals, surface plasmon polaritons provide a versatile and efficient tool due to the concentration of optical energy to subwavelength dimensions. Mott insulators, on the other hand are subject to strong exchange interactions. It is shown that the optical properties in these systems can be manipulated on timescales between 10 and 500 femtoseconds. In magnetic iron garnets, non-thermal ways for the optical control of the magnetization are investigated. The obtained knowledge is then combined with plasmonic enhancement with a view to ultrafast magnetic switching in modern data storage technologies.