The emergence of confined structures and pattern formation are exceptional manifestations of nonlinear interactions found in a variety of physical, chemical and biological systems¹. Facilitated by optical nonlinearities, solitons enable ultrashort temporal confinement of light and stable propagation despite the presence of dispersion. Such particle-like structures can assemble in stable arrangements, forming ‘soliton molecules’^2,3. Recent work has revealed oscillatory internal motions of these bound states, akin to molecular vibrations^4,5,6,7,8,9, raising the question of how far the ‘molecular’ analogy reaches, that is, whether further concepts from molecular spectroscopy apply and whether such intramolecular dynamics can be externally driven or manipulated. Here, we probe and control ultrashort bound states in an optical oscillator, using real-time spectral interferometry and time-dependent excitation. For a frequency-swept pump modulation, we analyse the nonlinear response and resolve anharmonicities in soliton interactions that lead to generation of overtones and sub-harmonics. Applying stronger stimuli, we demonstrate all-optical switching between states with different binding separations. These results could be applied to rapid pulse-pair generation and may stimulate the development of future instruments for ultrafast science.

受限结构的出现和图案的形成是在各种物理，化学和生物系统中发现的非线性相互作用的特殊表现¹。由于存在光学非线性，孤子可以实现光的超短时间限制和稳定的传播，尽管存在色散。这样的颗粒状结构可以以稳定的排列方式组装，形成“孤子分子” ^2,3。最近的工作揭示了这些键合态的内部振荡运动，类似于分子振动^4,5,6,7,8,9提出了“分子”类比方法达到多远的问题，即是否应用了分子光谱学的进一步概念，以及这种分子内动力学是否可以外部驱动或操纵。在这里，我们使用实时频谱干涉测量法和时间相关的激发来探测和控制光振荡器中的超短束缚状态。对于扫频泵浦调制，我们分析了非线性响应并解决了孤子相互作用中的不谐和现象，这导致了泛音和次谐波的产生。应用更强的刺激，我们证明了在具有不同结合间隔的状态之间的全光学切换。这些结果可用于快速脉冲对的产生，并可能刺激超快科学未来仪器的发展。