Evanescent-field illumination for Terahertz biological imaging

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.