We introduce a technique based on infrared thermal emission, termed depth thermography, that can remotely measure the temperature distribution beneath the surface of certain objects. Depth thermography utilizes the thermal-emission spectrum in the semitransparent spectral region of the target object to extract its temperature as a function of depth, in contrast with conventional thermography, which uses the spectrally integrated thermally emitted power to measure the surface temperature. Coupled with two-dimensional imaging, for example using an infrared hyperspectral camera or scanning a single-pixel spectrometer, this technique can yield volumetric temperature distributions. We carried out a proof-of-concept experiment on an asymmetrically heated fused-silica window, extracting the temperature distribution throughout the sample. Depth thermography may enable noncontact volumetric temperature measurements of microscopic objects such as multilayer electronic devices or macroscopic volumes of liquids and gases, as well as simultaneous all-optical measurements of optical and thermal properties of materials.

中文翻译：

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深度热成像：使用红外热辐射的无创3D温度分析

我们介绍了一种基于红外热辐射的技术，称为深度热成像技术，它可以远程测量某些物体表面下的温度分布。深度热成像技术利用目标物体的半透明光谱区域中的热发射光谱来提取其温度随深度的变化，而传统的热成像技术则使用光谱积分的热发射功率来测量表面温度。结合二维成像（例如使用红外高光谱相机或扫描单像素光谱仪），此技术可以产生体积温度分布。我们在不对称加热的熔融石英窗口上进行了概念验证实验，提取了整个样品的温度分布。