The Transregional Collaborative Research Center 173 Spin+X investigates spin properties from various perspectives and by connecting several scientific disciplines. Our Optical Quantum Metrology group at the RPTU in Kaiserslautern has been granted a project within the Research Center, with a total volume of 274.000 €.

In a collaborative effort, the groups of Professors Philipp Pirro, Martin Aeschlimann, Georg von Freymann and Ioachim Pupeza will study how photons in femtosecond laser pulses and terahertz (THz) radiation are converted into magnons. Ultrafast demagnetization induced by photons is a starting point for such photon-to-magnon conversion processes. The challenge in describing the entire multi-scale process comprehensively lies in the different perspectives used to describe the spin dynamics in the different scales. Complementing time-averaged Brillouin light scattering measurements of incoherent magnon spectra after irradiating the sample with a femtosecond laser pulse, and standard pump-probe measurements, our group will develop a novel single-shot electric-field-resolved technique to reveal incoherent (stochastic) magnetization dynamics with femtosecond temporal resolution. This will allow to distinguish the quenching of the longitudinal versus the stochastic ex-citation of the transversal component (i.e., spin wave excitation) of the magnetization.