The Talbot self-imaging effect is mostly present in the forms of space or time, or in the frequency domain by the Fourier duality. Here, we disclose a new spectral Talbot effect arising in optical orbital angular momentum (OAM) modes. The effect occurs in the context of petal-like beams, which are typically constructed from a number of in-phase equidistant OAM modes with at least one void mode in between. When illuminating such beams on phase masks that are azimuthally modulated with Talbot phases, the initial OAM modes are self-imaged to create new OAM modes, meanwhile preserving the initial OAM spectral profile. Such a phenomenon is theoretically predicted, and a close analogy is drawn with the spectral Talbot effect of frequency combs. The prediction is also experimentally confirmed by observing versatile spectral self-imaging on various optical petal-like beams.

中文翻译：

---

光学轨道角动量模式的光谱自成像

Talbot 自成像效应主要以空间或时间的形式存在，或通过傅里叶对偶性出现在频域中。在这里，我们公开了在光学轨道角动量 (OAM) 模式中出现的新光谱 Talbot 效应。这种效应发生在花瓣状光束的背景下，这些光束通常由许多同相等距 OAM 模式构成，中间至少有一个空模式。当在用 Talbot 相位进行方位角调制的相位掩模上照射此类光束时，初始 OAM 模式会自成像以创建新的 OAM 模式，同时保留初始 OAM 光谱轮廓。这种现象在理论上是可以预测的，并且可以与频率梳的频谱塔尔博特效应进行类比。