利用自发参量下转换产生795nm关联光子对的实验研究

The Experimental Investigation of 795 nm Correlation Photons Caused by Spontaneous Parametric Down-Conversion

本文进行了自发参量下转换(SPDC)产生795nm关联光子对的实验研究。选择Ⅱ类PPKTP晶体作为非线性介质,用倍频获得的397.5nm紫光作为泵浦光。在实验上首先通过符合计数测量了紫光单次穿过PPKTP晶体时SPDC过程产生的光子对亮度,当泵浦光功率为5mW时,测得符合计数为53 150/s。然后将下转换过程放入光学谐振腔中,对下转换光子的线宽进行压窄。实验上测得下转换光子对的关联时间为14.6ns,对应线宽约为15MHz。本文为纠缠光子对在Rb原子系综中的存储提供了实验基础。

In this paper,we presented an experimental research of 795 nm correlation photons caused by spontaneous parametric down-conversion（SPDC）. Selecting the Ⅱ class PPKTP crystal as the nonlinear medium and the 397. 5 nm violet light produced by frequency-doubling as the pump source. When the violet light through the PPKTP crystal in single, we measured the brightness of photons produced by the SPDC process through count we measured is coincidence counting in experiment. When the pump power is 5 mW, the coincidence 5 3150/s. We put the SPDC process in a optical cavity in order to narrow the line width of the conversion photons. The Correlation time of the conversion photons for H and V polarizations experimentally measured is 14. 6 ns, the width the time corresponds to is about 15 MHz. This paper provides an experimental foundation for the entangled photons being stored in the Rb atomic ensemble.