The valley degree of freedom^1,2,3,4 of electrons in materials promises routes towards energy-efficient information storage with enticing prospects for quantum information processing^5,6,7. Current challenges in utilizing valley polarization are symmetry conditions that require monolayer structures^8,9 or specific material engineering^10,11,12,13, non-resonant optical control to avoid energy dissipation and the ability to switch valley polarization at optical speed. We demonstrate all-optical and non-resonant control over valley polarization using bulk MoS_2, a centrosymmetric material without Berry curvature at the valleys. Our universal method utilizes spin angular momentum-shaped trefoil optical control pulses^14,15 to switch the material’s electronic topology and induce valley polarization by transiently breaking time and space inversion symmetry¹⁶ through a simple phase rotation. We confirm valley polarization through the transient generation of the second harmonic of a non-collinear optical probe pulse, depending on the trefoil phase rotation. The investigation shows that direct optical control over the valley degree of freedom is not limited to monolayer structures. Indeed, such control is possible for systems with an arbitrary number of layers and for bulk materials. Non-resonant valley control is universal and, at optical speeds, unlocks the possibility of engineering efficient multimaterial valleytronic devices operating on quantum coherent timescales.

材料中电子的谷自由度^1,2,3,4有望实现节能信息存储，并为量子信息处理带来诱人的前景^5,6,7。目前利用谷偏振的挑战是需要单层结构^8,9或特定材料工程^10,11,12,13的对称条件、避免能量耗散的非谐振光学控制以及以光速切换谷偏振的能力。我们展示了使用块状 MoS _2（一种在谷处没有贝里曲率的中心对称材料）对谷偏振的全光学和非谐振控制。我们的通用方法利用自旋角动量形状的三叶形光控制脉冲^14,15来切换材料的电子拓扑，并通过简单的相位旋转瞬时打破时间和空间反转对称性¹⁶来诱导谷极化。我们通过非共线光学探针脉冲的二次谐波的瞬态生成来确认谷偏振，具体取决于三叶形相位旋转。研究表明，对谷自由度的直接光学控制并不限于单层结构。事实上，对于具有任意层数的系统和散装材料来说，这种控制是可能的。非谐振谷控制是通用的，并且在光速下，开启了设计在量子相干时间尺度上运行的高效多材料谷电子器件的可能性。