摘要
锶原子(5s2)1S0-(5s5p)3P1互组跃迁自然线宽远窄于其单态间的(5s2)1S0-(5s5p)1P1偶极跃迁,在光频标中有着实际的应用。为获得该跃迁线的高质量光谱,从理论上分析了利用毛细管准直的热原子束中,锶原子(5s2)1S0-(5s5p)3P1互组跃迁荧光光谱的谱线增宽因素,包括多普勒增宽、激光线宽、饱和增宽和渡越增宽。利用不同准直度的原子束实验获得了该互组跃迁的荧光谱和饱和荧光谱,较高准直的原子束获得荧光谱线宽仅为6.5MHz,与饱和荧光谱的兰姆凹陷线宽(1.7 MHz)在同一个数量级上,大大减小了谱线的一阶多普勒增宽。通过对频率直接调制将激光器锁定在该谱线上,锁定后激光的线宽约为0.72MHz。
The strontium （5s2）1S0-（5s5p）3P1 intercombination transition is characterized far narrower natural line width than its counterpart dipode transition line （5s2）1S0-（5s5p）3P1 and has been applied in the field of optical frequency standards. In order to obtain its high quality spectrum, the line broadening factors of strontium （5s2）1S0-（5s5p）3P1 intercombination transition fluorescence spectrum are theoretically analyzed based on thermal atomic beam collimated by capillary tubes. The factors, including Doppler effect, laser line width, saturation broadening and transit-time broadening, are considered. Experimentally, the fluorescence spectrum including the saturated fluorescence spectrum, is obtained from the differently collimated strontium thermal atomic beams. The exprimental results show that the higher collimated thermal beam′s fluorescence spectrum line width is only 6.5 MHz, which is on the same order of magnitude as the Lamb-dip line width in the saturated fluorescence spectrum （1.7 MHz）, and greatly reduces first-order Doppler broadening of spectra. And an external cavity diode laser is locked to the narrow line fluorescence spectrum by modulating the laser′s frequency directly, achieving a laser line width of about 0.72 MHz.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2013年第6期327-335,共9页
Acta Optica Sinica
基金
国家自然科学基金(11074252
61127901)
中科院科研装备研制项目(YZ201115)资助的课题
关键词
激光光谱
谱线增宽
互组跃迁
原子束准直
laser spectroscopy
spectrum line broadening
intercombination transition
atomic beam collimation
