[论文解读] Ultrafast bursts of tailored spatiotemporal vortex pulses

Xin Liu, Chunhao Liang+3 more|arXiv (Cornell University)|Jul 29, 2024

Fluid Dynamics and Turbulent Flows被引用 6

一句话总结

作者通过实验生成带有皮秒级可切换横向 OAM 的超快时空涡旋脉冲，这使得可定制的时空 Laguerre-Gaussian 波包及手性控制成为可能。

ABSTRACT

Orbital angular momentums (OAMs) of light can be categorized into longitudinal OAM (L-OAM) and transverse OAM (T-OAM). Light carrying time-varying L-OAM, known as self-torqued light, was recently discovered during harmonic generation and has been extensively developed within the context of optical frequency combs (OFCs). Meanwhile, ultrafast bursts of optical pulses, analogous to OFCs, are sought for various light-matter interaction, spectroscopic and nonlinear applications. However, achieving transiently switchable T-OAM of light on request, namely spatiotemporal vortex pulse bursts, with independently controlled spatiotemporal profile of each comb tooth, remain unrealized thus far. In this work, the experimental generation of spatiotemporal vortex bursts featured with controllable time-dependent characteristics is reported. The resultant bursts comprised of spatiotemporal optical vortex comb teeth have picosecond timescale switchable T-OAMs with defined arrangement, manifesting as spatiotemporal torquing of light. We also show ultrafast control of T-OAM chirality, yielding pulse bursts with staggered azimuthal local momentum density, resembling Kármán vortex streets. This approach enables the tailoring of more intricate spatiotemporal wavepacket bursts, such as high-purity modes variation in both radial and azimuthal quantum numbers of spatiotemporal Laguerre-Gaussian wavepackets over time, which may facilitate a host of novel applications in ultrafast light-mater interactions, high-dimensional quantum entanglements, space-time photonic topologies as well as spatiotemporal metrology and photography.

研究动机与目标

• 激发在超快脉冲中瞬时可切换的横向 OAM（T-OAM）需求。
• 证明可控时间依赖特性的时空涡旋脉冲爆发的实验产生。
• 展示在涡旋脉冲爆发中，每个梳齿的时空轮廓独立可控。
• 探索随时间可定制径向与方位模分量以实现高纯度时空波包的能力。

提出的方法

• 产生带有可控时间依赖 T-OAM 的时空光学涡旋梳齿。
• 通过对涡旋梳齿的定义空间排列实现皮秒级可切换的 T-OAM。
• 操作 T-OAM 旋度以产生具有错位方位局部动量密度的脉冲爆发。
• 通过随时间改变径向和方位量子数来定制时空 Laguerre-Gaussian 波包。

实验结果

研究问题

• RQ1 是否能够产生每个梳齿的时空轮廓独立可控的时空涡旋脉冲爆发？
• RQ2 在实时条件下，是否能够实现并控于皮秒级切换横向 OAM？
• RQ3 是否能以超快速度控制 T-OAM 的手性，以产生类似卡门涡街的空间变化动量密度？
• RQ4 是否可以设计高纯度的时空 Laguerre-Gaussian 模式，使径向和方位量子数随时间变化？

主要发现

• 由带有皮秒级可切换 T-OAM 的涡旋梳齿组成、并具定义排序的时空涡旋脉冲爆发。
• 对 T-OAM 旋度的超快控制产生具有错位方位局部动量密度的脉冲爆发，类似卡门涡街。
• 通过随时间改变径向与方位量子数来定制高纯度时空 Laguerre-Gaussian 波包的能力。