Topological structures reveal the hidden secrets and beauty in nature, such as the double helix in DNA, whilst, the manipulation of which in physical fields, especially in ultrafast structured light, draw booming attention. Here we introduce a new family of spatiotemporal light fields, i.e. helical pulses, carrying sophisticated double-helix singularities in its electromagnetic topological structures. The helical pulses were solved from Maxwell’s equation as chiral extensions of toroidal light pulses but with controlled angular momentum dependence. We unveil that the double helix singularities can maintain their topological invariance during propagation and the field exhibits paired generation and annihilation of vortices and antivortices in ultrafast space-time, so as to be potential information carriers beating previous conventional vortex structured light.

中文翻译：

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时空螺旋脉冲中的双螺旋奇点和涡旋-反涡旋湮没


拓扑结构揭示了自然界中隐藏的秘密和美丽，例如 DNA 中的双螺旋结构，而在物理场中对其的操纵，尤其是在超快结构光中，引起了人们的广泛关注。在这里，我们介绍了一个新的时空光场系列，即螺旋脉冲，在其电磁拓扑结构中携带复杂的双螺旋奇点。螺旋脉冲由麦克斯韦方程求解为环形光脉冲的手性延伸，但具有受控的角动量依赖性。我们揭示了双螺旋奇点在传播过程中可以保持其拓扑不变性，并且场在超快时空中表现出漩涡和反涡的成对产生和湮灭，从而成为击败以前传统涡旋结构光的潜在信息载体。