Fabrication of Spin-Exchange-Relaxation-Free Atomic Magnetometer and Its Application

• Main Authors: Li, Chung-Lan, 李鍾嵐
• Other Authors: Pu, Nen-Wen
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/97939963469332895121

博士 === 國防大學理工學院 === 國防科學研究所 === 99 === Recent developments in the technology of atomic magnetometers have enabled them to surpass SQUID (superconductive quantum interference devices) as the most sensitive devices for detecting and measuring magnetic fields. Their sensitivity is limited by the relaxation due to spin-exchange collisions. In this study, we design and build a Rb atomic magnetometer operating in the spin-exchange-relaxation-free (SERF) regime. We demonstrate a Rb magnetometer in which spin-exchange relaxation is completely eliminated by operating at high Rb density and low magnetic field. A Rb cell was put inside a 5-layer magnetic shield, and three current coils were used to eliminate the residual magnetic field in the shield. The Rb cell was filled with 2 atm of He and 60 Torr of N2 to reduce the collisions of Rb atoms with the glass wall in order to avoid relaxation. The cell was heated to 160 ℃ to produce a high density Rb vapor. Two tunable diode lasers operating near the Rb D1 line were used for the pump and probe beams. The detection sensitivity determined by signal-to-noise measurements with an applied ac magnetic field of known magnitude was about 8 pT/(Hz)1/2.