Scanning thermal microscopy (SThM) is a powerful technique for obtaining local thermal information on a sample surface using a nano-fabricated thermometer probe. One important application of SThM is sub-wavelength optical imaging, which captures the photothermal response of the probe to light. In this nano-scale imaging technique, optical contrast and spatial resolution are critical performance indicators. The size and material of the thermometer probe play a significant role in determining image quality, as a smaller radius can improve spatial resolution but reduce optical contrast and sensitivity due to decreased light absorption. To address this challenge, we have developed an approach to improve the photothermal energy conversion efficiency by coating the probe with atomically thin graphene oxide (GO). Our results demonstrate that this GO coating can enhance optical sensitivity by more than 1.5 times with linear optical power dependency. Importantly, the coating significantly improves the root mean square contrast of the image by 2.56 times without compromising spatial resolution. Our study highlights the potential of GO-coated probes to improve the sensitivity and quality of SThM-based sub-wavelength optical imaging.

中文翻译：

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在扫描热显微镜中使用氧化石墨烯涂层探针增强亚波长光学图像的光学对比度

扫描热显微术 (SThM) 是一种强大的技术，可使用纳米制造的温度计探针获取样品表面的局部热信息。SThM 的一个重要应用是亚波长光学成像，它捕获探针对光的光热响应。在这种纳米级成像技术中，光学对比度和空间分辨率是关键的性能指标。温度计探头的尺寸和材料在确定图像质量方面起着重要作用，因为较小的半径可以提高空间分辨率，但由于光吸收减少而降低光学对比度和灵敏度。为了应对这一挑战，我们开发了一种通过在探针上涂上原子级薄的氧化石墨烯 (GO) 来提高光热能量转换效率的方法。我们的结果表明，这种 GO 涂层可以将光学灵敏度提高 1.5 倍以上，并具有线性光功率依赖性。重要的是，该涂层在不影响空间分辨率的情况下，将图像的均方根对比度显着提高了 2.56 倍。我们的研究强调了 GO 涂层探针在提高基于 SThM 的亚波长光学成像的灵敏度和质量方面的潜力。