Harmonic generation inside a non-collinear optical parametric oscillator

在前期工作中，对非共线相位匹配参量振荡器（NOPO）进行了多方面的研究。其中，提出了色散管理NOPO（DMNOPO）概念，这开辟了一种新的方法，从振荡器的几个光周期的持续时间的脉冲的功率缩放。DM-NOPO可以通过泵浦激光器轻松缩放，最终仅受组件损坏的限制。在本申请中，将寻求通过新的薄盘激光振荡器作为泵浦激光器的进一步功率缩放。在DMNOPO中循环的脉冲在谐振器中的一个点处聚焦成气体射流，在该点处脉冲具有几个周期的持续时间。在那里，可以而且应该研究振荡器重复频率下的强场效应。一种新型的双脉冲拓扑结构能够在惰性气体中非共线地产生辐射并有效地提取。其目的是研究谐波辐射的产生，最初是低阶的，后来是高阶的。特别感兴趣的是具有椭圆偏振的激光脉冲照射到目标中。初步的工作表明，有趣的信息电离动力学的意义上的光学attocock可以提取由此产生的偏振态的谐波。这项工作铺平了道路的高次谐波的产生和演示的真实的模式梳在XUV光谱范围内与共振增强的几个周期的脉冲。

In the preliminary work, the non-collinear phase-matched parametric oscillator (NOPO) was investigated in many ways. Among other things, a dispersion-managed NOPO (DMNOPO) concept was presented, which opens up a new approach to power scaling of pulses of a duration of a few optical cycles from an oscillator. The DM-NOPO can be easily scaled via the pump laser and is ultimately only limited by component damage. In the present application the further power scaling by a new thin-disk laser oscillator as a pump laser shall be pursued. The pulses circulating in the DMNOPO are focused into a gas jet at a point in the resonator where they have the few-cycle duration. There, strong-field effects at oscillator repetition rates can and shall be studied. A novel double pulse topology enables the non-collinear generation of radiation in noble gases and their efficient extraction. The aim is to study the generation of harmonic radiation, initially of a lower order and later of a higher order. Of particular interest is the irradiation of laser pulses with elliptical polarization into the target. The preliminary work has shown that interesting information about the ionization dynamics in the sense of an optical attoclock can be extracted from the resulting polarization state of the harmonics. This work paves the way for the generation of high order harmonics and the demonstration of a real mode comb in the XUV spectral range with resonantly enhanced few-cycle pulses.