极化^(3)He系统核磁共振FID信号的激光探测

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

极化率测量装置是极化^(3)He系统的重要组成部分之一.本文介绍了一套在极化^(3)He系统上搭建的激光探测自由感应衰减核磁共振(FID NMR)信号的实验装置,该装置有望为^(3)He极化率的高精度实时测量提供新的途径.激光探测法的原理是法拉第旋光效应,该方法使用一束线偏振光探测极化^(3)He磁矩绕主磁场进动的FID信号,实验结果表明相较于拾波线圈探测方法,激光探测方法的信噪比提高了106%,对^(3)He的极化率测量更精确.该探测方法有望替代传统的拾波线圈,广泛地应用于^(3)He极化系统的极化率测量或精密测量实验中.

Polarimetry is an important part of a polarized ^(3)He system.This work describes a laser detection setup which measures the free induction decay nuclear magnetic resonance(FID NMR)signal in the spin-polarized ^(3)He system.The setup provides a novel approach to the high precision real-time polarization measurement of the polarized ^(3)He 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 ^(3)He 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 ^(3)He 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 ^(3)He systems or in precision measurement experiments.