Distinguishing between the left- and right-handed versions of a chiral molecule (enantiomers) is vital, but also inherently difficult. Traditional optical methods using elliptically/circularly polarized light rely on linear effects which arise beyond the electric-dipole approximation, posing major limitations for ultrafast spectroscopy. Here we show how to turn an ultrashort elliptical pulse into an efficient chiro-optical tool: by tilting its polarization plane towards its propagation direction. This forward tilt can be achieved by focusing the beam tightly, creating structured light which exhibits a nontrivial polarization pattern in space. Using state-of-the-art computational modelling, we show that our structured field realizes a near-field interferometer for efficient chiral recognition that separates the nonlinear optical response of left- and right-handed molecules in space. Our work provides a simple, yet highly efficient, way of spatially structuring the polarization of light to image molecular chirality, with extreme enantio-efficiency and on ultrafast time scales.

中文翻译：

---

倾斜光的偏振面以在空间上分离手性分子的超快非线性响应

区分手性分子（对映异构体）的左手和右手版本至关重要，但本质上也很困难。使用椭圆/圆偏振光的传统光学方法依赖于超出电偶极子近似的线性效应，对超快光谱构成了主要限制。在这里，我们展示了如何将超短椭圆脉冲转变为有效的手性光学工具：通过将其偏振平面向其传播方向倾斜。这种向前倾斜可以通过紧密聚焦光束来实现，从而产生在空间中表现出非平凡偏振模式的结构光。使用最先进的计算模型，我们展示了我们的结构化场实现了一个近场干涉仪，用于有效的手性识别，分离空间中左手和右手分子的非线性光学响应。我们的工作提供了一种简单但高效的方法，可以在空间上构造光的偏振以成像分子手性，具有极高的对映效率和超快的时间尺度。