The Power of Light

The power of light

An all optical pump-probe method, using ultrashort photo-magnetic pulses (170 fs, at 800 nm), has been developed in order to study the ultrafast spin dynamics of single crystalline antiferromagnets over a broad temperature range. We envisage the technique as a flexible tool, as possible to adapt to the needs of fast physico-chemical processes involving classic and quantum states of chemically diverse systems.

Our results on orthoferrites (LnFeO3, Ln= Er, Y) show that this method is an efficient means for thermal control of the ultrafast oscillations of the antiferromagnetic spins on the local scale; the effects are manifested via the changes in the time-resolved (ps time-scale) linear magnetic birefringence of the materials. We demonstrate that a variant of this methodology, pertaining to the inverse Faraday effect, also achieves non-thermal control of the light-induced spin dynamical phenomena. We discuss how such manipulation of the magnetisation on the nanoscale, combined with the exchange-bias effect can play a key role towards the design of ultrafast magneto-optical switches in future storage devices.