Spin Exchange Relaxation Free (SERF) Magnetometers

Qian Cao, Ying Liu, Junjian Tang +3 more

Jiqing Fu, Pengcheng Du, Qing Zhou +1 more

The laser-pumped potassium spin-exchange relaxation free (SERF) magnetometer is the most sensitive detector of magnetic field and has many important applications.We present the experimental results of our potassium SERF magnetometer.A pump-probe approach is used to identify the unique spin dynamics of the atomic ensemble in the SERF regime.A single channel sensitivity of 8 f•THz -1/2 is achieved with our SERF magnetometer.

Junjian Tang, Ying Liu, Yaxiang Wang +4 more

We demonstrate the bandwidth enhancement of an all-optical spin-exchange relaxation-free (SERF) magnetometer based on amplitude-modulated (AM) light. Alkali metal atoms are modulated directly by the pump beam instead of the modulation field or radio frequency field. The first harmonic demodulation of an AM SERF magnetometer with a modulation intensity of 15 kHz results in a high bandwidth of over 11 kHz with a sensitivity of 20 fT/Hz1/2 at 30 Hz and 60 fT/Hz1/2 at 10 kHz. Meanwhile, the AM SERF magnetometer with DC demodulation presents the same sensitivity as a traditional DC SERF magnetometer (6 fT/Hz1/2 at 30 Hz). The presented technique for modulating the amplitude of the pump beam allows AM SERF magnetometers to enter the domain of high-bandwidth magnetometers and opens the door to many areas that are inaccessible to conventional magnetometers.

Cao Li, Junjian Tang, Yaohua Zhang +4 more

W. C. Griffith, Ricardo Jiménez-Martínez, Jan Preusser +2 more

Igor Savukov, Michael T. Ledbetter, Víctor M. Acosta +2 more

We have built and tested a Cs atomic magnetometer operating in the spin-exchange-relaxation-free (SERF) regime at much lower temperature than a more conventional potassium SERF magnetometer developed at Princeton University.