标题： 利用态的避免交叉精确测量超精细间隔 显示英文标题

标题： Precise measurement of hyperfine intervals using avoided crossing of dressed states

摘要： 我们展示了一种精确测量碱金属原子超精细间隔的技术。 在强控制激光和弱探测激光存在下，原子形成一个三级 $\Lambda$ 系统。 由控制激光产生的布居态显示出显著的线宽减小。 我们开发了一种多普勒自由光谱技术，即使在室温原子中也能高精度地测量布居态之间的分离。 当控制激光的失谐从正变到负时，这些态会经历一个避免交叉。 通过研究分离随失谐的变化，可以高精度地确定水平交叉图的中心，从而得到超精细间隔。 使用室温下的铷蒸气，我们获得了44 kHz的精度。 这比当前约1 MHz的精度有了显著提高。 显示英文摘要

摘要： We demonstrate a technique for precisely measuring hyperfine intervals in alkali atoms. The atoms form a three-level $\Lambda$ system in the presence of a strong control laser and a weak probe laser. The dressed states created by the control laser show significant linewidth reduction. We have developed a technique for Doppler-free spectroscopy that enables the separation between the dressed states to be measured with high accuracy even in room-temperature atoms. The states go through an avoided crossing as the detuning of the control laser is changed from positive to negative. By studying the separation as a function of detuning, the center of the level-crossing diagram is determined with high precision, which yields the hyperfine interval. Using room-temperature Rb vapor, we obtain a precision of 44 kHz. This is a significant improvement over the current precision of ~ 1 MHz.