从实验上定性地研究了强场谐波辐射过程中位相匹配的作用与影响,主要通过改变气体密度、激光强度和光束的共焦参数来研究相位匹配对高次谐波辐射的影响。从改善高次谐波辐射过程中的相位匹配来考虑,气体密度和激光强度都有一最佳值。利用大的共焦参数,可以明显改善相位匹配,提高谐波输出的转换效率

The phase matching effect on high order harmonic generation was studied by using a 45 fs 2 TW Ti:sapphire laser pulses, especially the effect of gas density, laser intensity and confocal parameter. It is found that there are an optimal gas density and an optimal laser intensity with regards to the improvement of phase matching. The weak focusing geometry is more favorable for higher conversion efficiency than the tight one.