Dual-Modulation Faraday Rotation Spectroscopy

摘要

A dual-modulation Faraday rotation spectroscopic (FRS) system is disclosed. The FRS system uses an FRS sample cell configured to subject a sample to a low frequency modulated magnetic field. The system includes a polarized laser light source configured to generate a high frequency wavelength-modulated light beam incident on the sample, the high frequency wavelength-modulated light beam being modulated at a higher frequency than the low frequency modulated magnetic field. A polarizer is configured to receive from the sample a transmitted light beam having a modulated polarization having a polarization rotation and translate the modulated polarization of the transmitted light beam into an intensity modulated beam. A photodetector is configured to detect the intensity modulated beam and generate a photodetector signal. A dual demodulator is coupled to the photodetector and is configured to demodulate the photodetector signal.

主权项

1. A Faraday rotation spectroscopic (FRS) system having an FRS sample cell configured to subject a sample to a low frequency modulated magnetic field, the system comprising:
a polarized laser light source configured to generate a high frequency wavelength-modulated light beam incident on the sample, the high frequency wavelength-modulated light beam being modulated at a higher frequency than the low frequency modulated magnetic field; a polarizer configured to receive from the sample a transmitted light beam having a modulated polarization and a polarization rotation and translate the modulated polarization of the transmitted light beam into an intensity modulated beam; a photodetector configured to detect the intensity modulated beam and generate a photodetector signal; a dual demodulator coupled to the photodetector and being configured to demodulate the photodetector signal.