Seres J, Seres E, Serrat C, Schumm T
Opt Express. 2018 Aug 20;26(17):21900-21909. doi: 10.1364/OE.26.021900.
We demonstrate non-perturbative 3rd (267 nm) and 5th (160 nm) harmonic generation in solids from a Ti:sapphire frequency comb (800 nm) at 108 MHz repetition rate. The experiments show that non-perturbative low harmonics are dominantly generated on the surface and on the interface between solids, and that they are not produced by bulk processes from the near-surface layer of the material. Measurements reveal that due to the lack of phase matching, the generated harmonics in bulk are suppressed by orders of magnitude compared to the signal generated on the surface. Our results pave the way for the development of all-solid-state high repetition rate harmonic sources for vacuum ultraviolet spectroscopy and high precision frequency comb metrology.
我们展示了在固体中从重复频率为108MHz的钛宝石频率梳（800nm）产生非微扰的三阶（267nm）和五阶（160nm）谐波。实验表明，非微扰低谐波主要在固体表面和固体之间的界面处产生，且并非由材料近表面层的体过程产生。测量结果显示，由于缺乏相位匹配，与表面产生的信号相比，体中产生的谐波被抑制了几个数量级。我们的结果为开发用于真空紫外光谱和高精度频率梳计量的全固态高重复率谐波源铺平了道路。
