Optical Excitation and Detection of Forward Spin Waves

ABSTRACT Optical excitation and detection of forward volume magnetostatic spin waves by femtosecond laser pulses are challenging as they require a special configuration of an optical scheme to perform both the launching of spin dynamics and its measurement as well. In this paper, we demonstrate excitation and detection of forward spin waves by using the oblique incidence of both pump and probe femtosecond pulses. The excited wave's propagation over 100 microns was demonstrated. Experimental analysis and theoretical calculations of the dispersion, group, and phase velocities verify the forward nature of the excited spin waves. This study opens a pathway for the utilization of forward spin wave configuration in various optomagnonics studies.