Observing the steady-state visual evoked potentials with a compact quad-channel spin exchange relaxation-free magnetometer

Du Peng-Cheng^{1, 3}, Li Jian-Jun^{1, 3}, Yang Si-Jia^{2, 4, 6}, Wang Xu-Tong¹, Zhuo Yan^{2, 4, 6}, Wang Fan^{2, 4, 5, 6, ‡}, Wang Ru-Quan^{1, 3, §}

The PSD of the output signal from channel-D of the OPM sensor at different visual stimuli frequencies: (a) 10 Hz, (b) 12.5 Hz, and (c) 15 Hz.