An Ultra-Narrow High-Power Faraday Laser Locked to the D₁ Line of Rubidium

We reported a new kind of 795 nm ultra-narrow external cavity diode lasers (ECDLs). A Faraday anomalous dispersion optical filter (FADOF) was used to construct the external cavity. The spectrum of the diode laser was strictly locked to the D1-line (~794.98 nm), and the bandwidth (FWHM) was narrowed from 2.5 nm in the free-running case to 0.005 nm (2.5 GHz) with a side mode suppression ratio of 26 dB. The final output power of the diode laser was 58 W, with an external cavity efficiency of 60%. The diode laser with such spectrum characteristics and output power could have wide applications, including biomedical magnetic resonance imaging (MRI), free-space optical communications, spin-exchange optical pumping, fundamental spin physics research, etc.