中文摘要：

自发拉曼散射是一种弱效应,在检测气体等低浓度物质时得到的信号往往非常微弱,很难辨识。针对这一问题,首先模拟了空心光子晶体光纤（HC-PCF）对激光能量密度的增强作用,讨论其与激光束耦合联接的条件,然后用HC-PCF作样品气的腔体,设计出一种与激光谐振腔部分重叠的反射腔,对样气中的氮气浓度进行检测。试验结果表明：把空心光子晶体光纤和反射腔结合起来可以有效增强自发拉曼信号的产生,且适用于气体浓度检测。

英文摘要：

Spontaneous Raman scattering is a kind of weak effect so that signals from detecting substances with low concentra- tion such as gas are often very weak ,and they are difficult to identify.In order to solve the problem ,the enhanced effect on laser en- ergy density in HC-PCF was simulated and the condition of connecting HC-PCF with laser beam was discussed.Then we invented a kind of reflection which is part overlap with laser cavity using HC-PCF as sample gas cavity to test the nitrogen concentration. The experimental results show that the method combining HC-PCF and reflective cavity can effectively increase the spontaneous Raman signal and is suitable for the gas concentration detection.