Enhanced harmonic generation by breaking the phase-matching symmetry.
Enhanced harmonic generation by breaking the phase-matching symmetry.
复制标题
通过打破相位匹配对称性来增强谐波产生。
作者：
G. Gibson;N. Majtenyi;E. Sergan
本文介绍了在紧聚焦极限下利用聚焦高斯光束产生三次谐波时打破相位匹配对称性的两种静态方法，大大提高了转换效率和模式质量。两者都依赖于抑制光束腰后立即产生的谐波，防止从聚焦前后近乎完美地消除三次谐波产生(THG)。第一种方法包括在腰部放置一个薄的金属隔膜：激光在一个小针孔上钻孔，进而扰乱针孔后的光束聚焦。第二种方法是在焦点之前放置一个大的χ(3)气体，在焦点之后放置一个小的χ(3)气体。
We introduce two static methods to break the phase-matching symmetry in third harmonic generation with a focused Gaussian beam in the tight focusing limit, dramatically increasing the conversion efficiency and mode quality. Both rely on inhibiting harmonic generation immediately after the beam waist, preventing the near perfect cancellation of the third harmonic generation (THG) from before and after the focus. The first method involves placing a thin metal septum at the waist: the laser drills a small pinhole, which, in turn, disrupts the beam focus after the pinhole. The second method is based on placing a large χ(3) gas before the focus and a small χ(3) gas after the focus.