Modern quantum technologies rely crucially on techniques to mitigate quantum decoherence; these techniques can be either passive, achieved for example via materials engineering, or active, typically achieved via pulsed monochromatic driving fields applied to the qubit. Using a solid-state defect spin coupled to a microwave-driven spin bath, we experimentally demonstrate a decoherence mitigation method based on spectral engineering of the environmental noise with a polychromatic drive waveform, and show that it outperforms monochromatic techniques. Results are in agreement with quantitative modeling, and open the path to active decoherence protection using custom-designed waveforms applied to the environment rather than the qubit.

现代量子技术严重依赖于减轻量子退相干的技术；这些技术可以是被动的，例如通过材料工程实现，也可以是主动的，通常通过应用于量子比特的脉冲单色驱动场实现。使用与微波驱动旋转浴耦合的固态缺陷自旋，我们通过实验证明了一种基于环境噪声频谱工程的退相干缓解方法，该方法具有多色驱动波形，并表明它优于单色技术。结果与定量建模一致，并为使用应用于环境而不是量子位的定制设计波形开辟了主动退相干保护的道路。