Evanescent-field illumination for Terahertz biological imaging

太赫兹(THz)辐射是波长在300微米到100微米之间的辐射。它具有成像的前景，因为它是非电离的(不同于X射线)，并且可以穿透许多光学不透明的介质。与光学成像相比，自由空间太赫兹成像的一个限制是分辨率较低。提高分辨率的行业标准技术是近场栅格扫描，它将低于所谓的衍射极限的分辨率提高到几十微米。然而，这种改进是以时间为代价的。这项博士研究计划将着眼于逝去场照明技术(通过周期结构中的全内反射和表面模式)以及最先进的THz相机，以在不需要近场光栅扫描的情况下实现更高的空间分辨率。这位博士生将使用商用全光纤耦合太赫兹时域光谱仪和连续波IMPATT二极管光源以及太赫兹相机，设计、建模和实现高分辨率太赫兹显微镜。显微镜的成像能力将使用生物样本进行测试。

Terahertz (THz) radiation is radiation with a wavelength between 300 and 100 micrometres. It holds promise for imaging since it is nonionizing (unlike X-rays) and can penetrate through many optically opaque media. A limitation of free-space THz imaging is poor resolution compared to optical imaging. The industry standard technique for improving resolution is near-field raster-scanning which improves the resolution below the so-called diffraction limit to a few tens of micrometres. However, this improvement comes at the expense of time. This PhD research programme will look at evanescent-field illumination techniques (via total internal reflection and surface modes in periodic structures) along with state-of-the-art THz cameras to achieve an improved spatial resolution without the need for near-field raster scanning. Using a commercial all fibre-coupled Terahertz time-domain spectrometer and CW IMPATT diode sources along with a THz camera, the PhD student will design, model and implement a high-resolution THz microscope. The imaging capabilities of the microscope will be tested using biological samples.