The interplay of chiralities in light and quantum matter provides an opportunity to design and manipulate chirality-dependent properties in quantum materials. Herein we report the chirality-dependent Floquet engineering on topological fermions with the high Chern number in chiral crystal CoSi via circularly polarized light (CPL) pumping. Intense light pumping does not compromise the gapless nature of topological fermions in CoSi, but displaces the crossing points in momentum space along the direction of light propagation. The Floquet chirality index is proposed to signify the interplay between the chiralities of topological fermion, crystal, and incident light, which determines the amplitudes and directions of light-induced momentum shifts. Regarding the time-reversal symmetry breaking induced by the CPL pumping, momentum shifts of topological fermions result in the birth of transient anomalous Hall signals in non-magnetic CoSi within an ultrafast time scale, which Mid-infrared (IR) pumping and terahertz (THz) Kerr or Faraday probe spectroscopy could experimentally detect. Our findings provide insights into exploring novel applications in optoelectronic devices by leveraging the degree of freedom of chirality in the non-equilibrium regime.

光和量子物质中手性的相互作用为设计和操纵量子材料中的手性依赖性特性提供了机会。在此，我们通过圆偏振光 （CPL） 泵浦报道了手性依赖性在手性晶体 CoSi 中具有高陈数的拓扑费米子上的手性依赖性 Floquet 工程。强光泵浦不会损害 CoSi 中拓扑费米子的无间隙性质，而是沿光传播方向移动动量空间中的交叉点。Floquet 手性指数被提出来表示拓扑费米子、晶体和入射光的手性之间的相互作用，这决定了光诱导动量偏移的幅度和方向。关于 CPL 泵浦引起的时间反转对称性破坏，拓扑费米子的动量偏移导致在超快时间尺度内非磁性 CoSi 中产生瞬态异常霍尔信号，中红外 （IR） 泵浦和太赫兹 （THz） 克尔或法拉第探针光谱可以通过实验检测到。我们的研究结果为利用非平衡状态下的手性自由度来探索光电器件中的新应用提供了见解。