Dual-beam room-temperature atomic magnetometer with high-sensitivity and large dynamics range


 We demonstrate a dual-beam high-sensitivity room temperature atomic magnetometer (AM) with large dynamic range based on nonlinear magneto-optical rotation (NMOR) enhancing scheme. Using an inelastic wave-mixing laser, we find significant NMOR signal enhancement compared with a single-beam scheme under the same far-detuned operation conditions. This dual-beam scheme is taken to operate well in the regime of lower laser intensity and off-resonance detuning. The best sensitivity achieved is 20 fT/Hz1/2 with a bandwidth of 2 kHz, substantially greater than common spin exchange relaxation free AMs. This gives a pathway to develop low-power, inexpensive miniaturized AMs for wide application.