Research on Solid-state Optical Filtering Technology Using Faraday Anomalous Dispersion in Rare Earth-doped Crystals

Abstract

This paper proposes a Faraday anomalous dispersion optical filter that uses rare earth-doped crystals to overcome the limitations of current atomic filtering technology, which include limited working wavelength and Doppler broadening. The paper analyses Er3+: LiYF4 1530 nm as an example filter. The results show that the proposed filter achieves high transmission while maintaining an ultra-narrow bandwidth transmission spectrum. The maximum transmission efficiency reaches 94.8% with a transmission bandwidth of hundred trillions HZ. The position of the transmission peak can be tuned by adjusting the size of the magnetic field, enabling the conversion of the transmission spectrum between the line center and the line wing.