arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1902.02620physics.optics
收藏

蓝光超快高阶矢量涡旋光束的单程二次谐波产生

Single-pass, second harmonic generation of ultrafast, higher order vector vortex beams at blue

Ravi Kiran Saripalli, Anirban Ghosh, N. Apurv Chaitanya, G. K. Samanta

摘要:

报道了一种新的蓝光矢量涡旋光束单次倍频的实验方案。利用脉宽约17 fs的钛宝石超快激光器和一组螺旋相位板,在偏振马赫-曾德尔干涉仪(MZI)中,在平均功率为860 mW的条件下,获得了lp = 12阶矢量涡旋光束。考虑到矢量涡旋光束的空间偏振特性,以及非线性频率转换过程对相互作用光束偏振特性的依赖性,利用两个光轴相互正交的硼酸铋晶体,将近红外矢量涡旋光束倍频为可见光矢量涡旋光束,倍频阶数高达lsh=24.实验测得lsh =2的矢量涡旋光束在单程倍频效率为2.4%时的最大输出功率为20.5mW。通过控制MZI中的时间延迟,我们在超快时间尺度上保持了泵浦光束和倍频光束的矢量涡旋性质。模式纯度的测量证实了高质量的矢量涡旋光束在泵浦和倍频波长的产生。通用的实验方案可以用来产生跨电磁波谱的矢量涡旋光束。

英文摘要:

We report a novel experimental scheme for single-pass second harmonic generation (SHG) of vector vortex beam in the blue. Using an ultrafast Ti:Sapphire laser of pulse width ~17 fs and a set of spiral phase plates in polarization based Mach-Zehnder interferometer (MZI) we have generated vector vortex beams of order as high as lp = 12 at an average power of 860 mW. Given the space-variant polarization of the vector vortex beam, and the dependence of nonlinear frequency conversion processes on the polarization of the interacting beams, using two contiguous bismuth borate crystals with optic axis orthogonal to each other, we have frequency-doubled the near-IR vector vortex beam into visible vector vortex beams with order as high as lsh=24. The maximum output power of the vector vortex beam of order, lsh =2 is measured be as high as 20.5 mW at a single-pass SHG efficiency of 2.4 %. Controlling the temporal delay in the MZI, we have preserved the vector vortex nature of the beams at both pump and frequency-doubled beams at ultrafast timescales. The measurement on mode purity confirms the generation of high quality vector vortex beams at pump and SHG wavelengths. The generic experimental scheme can be used to generate vector vortex beams across the electromagnetic spectrum.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑