[26a-E201-1~12] 10.2 Fundamental and exploratory device technologies for spin

△ [26a-E201-1] Ultrafast time-resolved spectroscopy of spin precession by asynchronous optical sampling measurement using dual frequency comb

〇(D)Daichi Nishikawa¹, Makoto Okano^1,2, Shinichi Watanabe¹ (1.Keio Univ., 2.Bouei Univ.)

Keywords:spin precession, dual-comb, asynchronous sampling

Time-resolved spectrocopy of the dynamics of photo-excited spin precession on a ferromagnetic metal NiFe surface were performed. A dual-comb light source consisting of two optical frequency comb light sources was used for the experiments.By controlling the timing of the pulse oscillation of each light source with precise frequency stabilization, a time difference was automatically generated between the pump and probe light pulses, and pump-probe spectroscopy with non-mechanical time sweep was realized. In other words, we have constructed an asynchronous sampling measurement system. In this way, the measurement time of the optical pump-probe method was shortened and the time and frequency resolutions were improved. We succeeded in observing photo-excited spin precession and ultrafast demagnetization.