Abstract
The main work of this thesis is one of the bases for a biphoton single-photon source experiment in hot rubidium atoms. Due to Doppler effect, the thermal atomic motion causes additionally-absorbed loss for the light field, which may be fatal for a photon-level experiment and lead to a complete failure in experiment. Therefore, it is necessary to improve the Electromagnetic Induced Transparency (EIT) performance to achieve a sufficiently high degree of transparency. In this thesis, a Λ-type model is used to demonstrate EIT and population must be concentrated in one single Zeeman state in order to get the closest interaction between light and atoms with theoretical model. The main contents of this thesis is using optical pumping to make the population concentrated in the |5S1/2F=2，m=2>. We improve the pumping effect for high-speed atoms, via compensating geomagnetic field to reduce Larmor precession and using a high-frequency sine-wave modulated pump field to make the population could be concentrated in the |5S1/2F=2，m=2>. Finally, we observe the optimal EIT spectrum with 76% transmission.