Laser Detection of Nuclear Magnetic Resonance FID Signal for Polarized 3He System

Abstract

Polarimetry is an important part of a polarized 3He system. This work describes a laser detection setup which measures the free induction decay nuclear magnetic resonance (FID NMR) signal in the spin-polarized 3He system. The setup provides a novel approach to the high precision real-time polarization measurement of the polarized 3He systems. This laser detection method is based on Faraday rotation effect, which utilizes a linearly polarized laser beam to detect the FID signal of the magnetic moment of 3He atoms which precess along the direction of the main magnetic field. Compared with traditional pick-up coils, experimental results demonstrate that the laser detection method has a signal-to-noise ratio improvement of 106% and consequently higher precision in 3He polarization measurement. The laser detection method proposed in this paper can replace the pickup coils, and it has various applications in the polarization measurement of 3He systems or in precision measurement experiments.

Keywords

• polarized 3he
• free induction decay nuclear magnetic resonance (fid nmr)
• laser detection
• faraday optical rotation effect