Kudryashov Sergey, Rupasov Alexey, Zakoldaev Roman, Smaev Mikhail, Kuchmizhak Aleksandr, Zolot'ko Alexander, Kosobokov Michail, Akhmatkhanov Andrey, Shur Vladimir
Lebedev Physical Institute, 119991 Moscow, Russia.
School of Natural Sciences and Mathematics, Ural Federal University, 620000 Ekaterinburg, Russia.
Nanomaterials (Basel). 2022 Oct 15;12(20):3613. doi: 10.3390/nano12203613.
The inscription regimes and formation mechanisms of form-birefringent microstructures inside nano-porous fused silica by tightly focused 1030- and 515-nm ultrashort laser pulses of variable energy levels and pulsewidths in the sub-filamentary regime were explored. Energy-dispersion X-ray micro-spectroscopy and 3D scanning confocal Raman micro-spectroscopy revealed the micro-tracks compacted by the multi-shot laser exposure with the nanopores hydrodynamically driven on a microscale to their periphery. Nearly homogeneous polarimetrically acquired subwavelength-scale form-birefringence (refractive index modulation ~10) was simultaneously produced as birefringent nanogratings inside the microtracks of wavelength-, energy- and pulsewidth-dependent lengths, enabling the scaling of their total retardance for perspective phase-modulation nanophotonic applications. The observed form-birefringence was related to the hierarchical multi-scale structure of the microtracks, envisioned by cross-sectional atomic-force microscopy and numerical modeling.
研究了在亚丝状区域中，通过具有可变能量水平和脉宽的1030纳米和515纳米紧聚焦超短激光脉冲，在纳米多孔熔融石英内部形成形状双折射微结构的铭刻机制和形成机理。能量色散X射线显微光谱和三维扫描共焦拉曼显微光谱揭示了多次激光曝光压实的微轨迹，纳米孔在微观尺度上通过流体动力学作用被驱动到其周边。作为双折射纳米光栅，在波长、能量和脉宽依赖长度的微轨迹内部同时产生了几乎均匀的偏振获得的亚波长尺度形状双折射（折射率调制~10），从而能够为透视相位调制纳米光子应用缩放其总相位延迟。通过横截面原子力显微镜和数值模拟所设想的，观察到的形状双折射与微轨迹的分级多尺度结构有关。
