Multicolored optical switching phenomena are crucial for a broad range of applications, such as telecommunications and optical computing. However, most materials typically exhibit single-colored optical nonlinearity under intense laser illumination. Herein, our femtosecond time-resolved transient transmission measurements reveal the coexistence of the transient Pauli blocking effect in both the $\mathrm{\Gamma }$ and $L$ valleys following intense optical excitation in $\mathrm{Ge}$ films, demonstrating their feasibility as multicolored optical switching materials based on multivalley scattering. Additionally, a split-off energy of 240 meV at the $L$ point, attributed to the spin-orbit coupling effect, is directly observed from time-resolved transient transmission spectra. Based on an accurately calculated band structure, a scheme has been developed to interpret pump-probe transient transmission traces, effectively avoiding overinterpretation of overlapping transient signals caused by multiple-transition pathways. Furthermore, analysis of transmission transients using a three-level model indicates that the intervalley scattering time between the $\mathrm{\Gamma }$ and $L$ valleys is within 196 fs, and the intravalley scattering time is within 1.10 ps in the $\mathrm{\Gamma }$ valley, highlighting the potential for achieving an ultrafast multicolored optical switching device for key applications in multiband communications and optical computing.

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• Carrier dynamics
• Light propagation, transmission & absorption
• Optoelectronics
• Spin-orbit coupling
• Valleytronics
• Elemental semiconductors
• Density functional calculations
• Ultrafast femtosecond pump probe