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, §}

Experimental equipment for detecting the SSVEP response. (a) Magnetometer is placed at the human head; (b) schematic technical drawing of the compact quad-channel SERF magnetometer; (c) black and white grid for visual stimulation; (d) magnetically shielded room.