论文标题
由圆形极化激光脉冲辐射的微质量波导产生的强烈高谐波光学涡旋
Intense high-harmonic optical vortices generated from a micro-plasma-waveguide irradiated by a circularly polarized laser pulse
论文作者
论文摘要
提出了一种生成强烈的高谐波光学涡旋的方案。当相对性圆形极化激光脉冲辐照微等位 - 波 - 波基时，它依赖于光的自旋轨道相互作用。强烈的激光场在波导的内部边界处驱动强烈的表面波，这导致高阶谐波产生，因为激光在内部传播。对于圆两极化的驱动激光器，光学手性印在表面波，这有助于将基本光的旋转角动量转化为谐波的轨道角动量。开发了一个“摇摆的波导”模型，表明上述现象是由于非线性血浆响应而产生的，该响应会在高强度下修改电磁模式。我们进一步显示所有谐波梁的相速度自动与驱动激光器匹配，因此谐波强度随传播距离而增加。谐波产生的效率与表面波破裂效应有关，这种效应可以使用紧密聚焦的激光显着提高。我们的模拟表明可以实现总体转换效率$ \ sim5 \％$。
A scheme for generating intense high-harmonic optical vortices is proposed. It relies on spin-orbit interaction of light when a relativistically-strong circularly polarized laser pulse irradiates a micro-plasma-waveguide. The intense laser field drives a strong surface wave at the inner boundary of the waveguide, which leads to high-order harmonic generation as the laser traveling inside. For a circularly polarized drive laser, the optical chirality is imprinted to the surface wave, which facilitates conversion of spin angular momentum of the fundamental light into orbital angular momenta of the harmonics. A "shaken waveguide" model is developed showing that the aforementioned phenomena arises due to nonlinear plasma response that modifies electromagnetic mode at high intensities. We further show the phase velocities of all the harmonic beams are automatically matched to the driving laser, so that the harmonic intensities increase with propagation distance. The efficiency of harmonic production are related to the surface wave breaking effect, which can be significantly enhanced using a tightly focused laser. Our simulation suggests an overall conversion efficiency $\sim5\%$ can be achieved.
