This paper reports on the excited state Faraday anomalous dispersion spectrum (FADS) of rubidium based on transition 5P3/2→5D5/2. Theoretical analysis and experimental studies have been made. The results showed that the peak transmission occurred at the central frequency of the transition, there was an optimal magnetic intensity at a certain temperature and pump power, and peak transmission increased with the enhancement of pump power. 16% transmission was predicted when the density of 5P3/2 atoms was sufficient.

Coherent optical communications systems are of higher sensitivity than that in systems employing the direct detection. However, interferences such as the wavefront distortion and the random vibration of polarization caused by the turbulent atmosphere limit the development of terrestrial coherent wireless optical communications system. This paper presents a novel heterodyne optical wireless communications system and method based on the grating writing and reading of the multiple-quantum-we Udevice (MQW). The MQW, a new generation of photoelec-tric device developed in 1990's, is of the attractive features including high sensitivity and fast response. Compared with the conventional coherent detection method, our method eliminates the complicated intermediate-frequency tracking system. Experimental results show that our method can repress the wavefront distortion introduced in transmission through the atmosphere.