This project will develop the first adaptive optics for the terahertz (THz) band of the electromagnetic spectrum, using nematic liquid-crystal devices. The THz band lies between the infrared and microwave regions and represents a meeting between electronic and optical technologies. Although numerous potential applications for THz sensing exist, including atmospheric and space research, security and biomedical imaging, and industrial inspection, there has been limited practical use of THz systems outside specialised laboratories. One key reason for this is the poor availability of optical components to guide, control and manipulate THz radiation. Specifically, THz systems rely on large and complex assemblies of fixed metallic reflectors or polymeric lenses, which can only be adjusted using slow and power-hungry mechanical positioners. In this project, the student will develop an entirely new adaptive-optics (AO) approach to system control, in which the optical properties of compact optical components can be adjusted dynamically using a simple electrical bias. The student will develop a range of AO components and systems, using nematic liquid crystals devices (LCDs) —a technique that has had considerable success in infrared and visible optics. These materials are fluids consisting of rod-like molecules, which preferentially align with each other along their long axes, resulting in anisotropic optical properties that can also be adjusted by applying a bias voltage. Initially, the student will study the properties of LC materials, using broadband THz time-domain spectroscopy to characterise, catalogue and improve their performance in the THz band. The most successful materials will be used to construct AO devices, including variable waveplates and attenuators, and spatial-light modulators, the first of their kind in this spectral band, and use them to demonstrate advanced applications including dynamic beam steering and circular dichroism spectroscopy.
Further information about this project and how to apply can be found on our website.
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