Atomic force microscope generally works by manipulating the absolute magnitude of the van der Waals force between tip and specimen. This force is, however, less sensitive to atom species than to tip-sample separations, making compositional identification difficult, even under multi-modal strategies or other atomic force microscopy variations. Here, we report the phenomenon of a light-modulated tip-sample van der Waals force whose magnitude is found to be material specific, which can be employed to discriminate heterogeneous compositions of materials. We thus establish a near-field microscopic method, named light-modulated van der Waals force microscopy. Experiments discriminating heterogeneous crystalline phases or compositions in typical materials demonstrate a high compositional resolving capability, represented by a 20 dB signal-to-noise ratio on a MoTe₂ film under the excitation of a 633 nm laser of 1.2 mW, alongside a sub-10 nm lateral spatial resolution, smaller than the tip size of 20 nm. The simplicity of the light modulation mechanism, minute excitation light power, broadband excitation wavelength, and diversity of the applicable materials imply broad applications of this method on material characterization, particularly on two-dimensional materials that are promising candidates for next-generation chips.

原子力显微镜通常通过操纵针尖和样品之间范德华力的绝对大小来工作。然而，这种力对原子种类的敏感性不如对针尖-样品分离敏感，这使得成分鉴定变得困难，即使在多模态策略或其他原子力显微镜变化下也是如此。在这里，我们报告了光调制尖端样本范德华力的现象，其大小被发现是特定于材料的，可用于区分材料的异质成分。因此，我们建立了一种近场显微方法，称为光调制范德华力显微镜。区分典型材料中的异质晶相或成分的实验表明，MoTe 2 薄膜具有很高的成分分辨能力，在 1.2 mW 的 633 nm 激光器激发下，MoTe₂ 薄膜上的 20 dB 信噪比，以及小于 20 nm 针尖尺寸的亚 10 nm 横向空间分辨率。光调制机制的简单性、微小的激发光功率、宽带激发波长和适用材料的多样性意味着该方法在材料表征方面的广泛应用，特别是在二维材料上，这些材料是下一代芯片的有前途的候选者。