论文标题
第二次谐波产生的角动量从低密度的等离子体中保存
Conservation of angular momentum in second harmonic generation from under-dense plasmas
论文作者
论文摘要
光束的自旋和轨道角动量是两个独立参数，对机械物体表现出明显的影响。但是，当激光束具有角动量与等离子体相互作用时，可以观察到自旋和轨道角动量之间的相互作用。在这里，通过测量使用已知的自旋和轨道角动量泵束在不足的血浆中产生的第二个谐波2Ω辐射的螺旋相，我们验证了光子的总角动量是保守的，并观察到自旋转换为轨道角动量。我们通过分析2Ω光的近场强度分布来进一步确定2Ω光子的源。 2Ω图像与这些光子在血浆中最大的泵束强度梯度附近产生的相一致，这是使用laguerre-gaussian梁的旋转和轨道角动量的组合效应所预测的。
Spin and orbital angular momentum of an optical beam are two independent parameters that exhibit distinct effects on mechanical objects. However, when laser beams with angular momentum interact with plasmas, one can observe the interplay between the spin and the orbital angular momentum. Here, by measuring the helical phase of the second harmonic 2ω radiation generated in an underdense plasma using a known spin and orbital angular momentum pump beam, we verify that the total angular momentum of photons is conserved and observe the conversion of spin to orbital angular momentum. We further determine the source of the 2ω photons by analyzing near field intensity distributions of the 2ω light. The 2ω images are consistent with these photons being generated near the largest intensity gradients of the pump beam in the plasma as predicted by the combined effect of spin and orbital angular momentum when Laguerre-Gaussian beams are used.
