中文摘要：

通过吸收成像方法,统计探测光对原子气体的加热损耗,在-（87）Rb玻色-爱因斯坦凝聚体中观察到电磁诱导透明现象。观察电磁诱导透明现象的常规方法是测量探测光的透射光谱,但是对于玻色-爱因斯坦凝聚体这种易受外界干扰的研究对象,应用吸收成像的方法更加简单适用。实验发现,经过透镜聚焦后耦合光的光斑大小强烈影响电磁诱导透明的线型。改变探测光的偏振状态,在电磁诱导透明的峰值处观察到拉曼跃迁过程。拉曼跃迁过程使电磁诱导透明窗口出现极窄的吸收线。相比于电磁诱导透明效应,在拉曼跃迁机制下,探测光的色散曲线更加陡峭,可实现更高效的光减速效果。在双光子共振处,通过改变探测光的偏振状态从而改变其吸收与色散性质,可构造光学开关和光偏振的光致旋转。

英文摘要：

We have observed electromagnetically induced transparency in 87 Rb Bose-Einstein condensate when measuring the loss effect introduced by probe light on ultracold atomic gases in the method of absorption imaging.As an alternative way of a usual method,which measures the transmission spectrum of probe light to verify the EIT effect,this method we take is specially suitable for ultracold atomic gases which is very likely to be destroyed by external perturbation.We find that the lineshape of EIT spectrum is relied on the divergence of couple light which is focused by a lens.When rotating the polarization of probe light,Raman transition appears in the peak of EIT spectrum.Raman transition introduces quite narrow absorption line in EIT window.Compared with EIT effect,Raman transition leads to a much more steep dispersion curve of probe light,so a better slow-light effect can be achieved.Furthermore,since probe light in different polarization experiences different absorption and dispersion property in the condition of two-photon resonance,optical switching and optical rotation of probe beam＇s polarization can be constructed.