论文标题
一种零时的时空显微镜技术，用于超敏化薄膜热扩散性的超敏测度
A pre-time-zero spatiotemporal microscopy technique for the ultrasensitive determination of the thermal diffusivity of thin films
论文作者
论文摘要
扩散是本质上最普遍的运输现象之一。在实验上，可以通过在空间和时间上进行以下点扩展来跟踪它。在这里，我们介绍了一种时空泵送显微镜技术，该技术利用当探针脉冲到达泵脉冲之前时通过短暂反射率获得的残留空间温度曲线。这对应于有效的泵探针时间延迟13 ns，这取决于我们的激光系统的重复率（76 MHz）。这种零时的技术使得可以探测先前具有纳米精度的先前泵脉冲产生的长寿命激发的扩散，并且对于遵循薄膜中的平面热扩散特别有力。与量化热传输的现有技术相反，它不需要任何材料输入参数或强加热。 We demonstrate the direct determination of the thermal diffusivities of the layered materials MoSe$_2$ (0.18 cm$^2$/s), WSe$_2$ (0.20 cm$^2$/s), MoS$_2$ (0.35 cm$^2$/s), and WS$_2$ (0.59 cm$^2$/s).该技术为观察新型纳米级热传输现象和跟踪广泛物种的扩散铺平了道路。
Diffusion is one of the most ubiquitous transport phenomena in nature. Experimentally, it can be tracked by following point spreading in space and time. Here, we introduce a spatiotemporal pump-probe microscopy technique that exploits the residual spatial temperature profile obtained through the transient reflectivity when probe pulses arrive before pump pulses. This corresponds to an effective pump-probe time delay of 13 ns, determined by the repetition rate of our laser system (76 MHz). This pre-time-zero technique enables probing the diffusion of long-lived excitations created by previous pump pulses with nanometer accuracy, and is particularly powerful for following in-plane heat diffusion in thin films. In contrast to existing techniques for quantifying thermal transport it does not require any material input parameters or strong heating. We demonstrate the direct determination of the thermal diffusivities of the layered materials MoSe$_2$ (0.18 cm$^2$/s), WSe$_2$ (0.20 cm$^2$/s), MoS$_2$ (0.35 cm$^2$/s), and WS$_2$ (0.59 cm$^2$/s). This technique paves the way for observing novel nanoscale thermal transport phenomena and tracking diffusion of a broad range of species.
