Researchers at the Tokyo Institute of Technology and Nippon Telegraph and Telephone Corporation have developed a “spin-resolved oscilloscope.” This device is a basic measuring instrument for plasmonics and spintronics, which are key technologies for future electronics applications. The coupling of light and electronic charges in plasmonics will pave the way for ultra-high-speed information processing, whereas spintronics will provide low-energy-consumption technology in a highly information-oriented society. The spin-resolved oscilloscope pioneers future “spin-plasmonics,” where ultra-high-speed low-energy-consumption devices will be achieved.