Presentation description

Historically, terahertz (THz) waves have found many applications in imaging and spectroscopy, but have recently seen an increase in potential for mobile communications. In the Terahertz regime, signals are much more efficient in terms of bandwidth, transmission windows, and absorption loss and thus provide a strong solution to 6G communications. However, this spectral regime does not come without issues. Having a larger wavelength than traditional RF and microwave signals, Terahertz waves must be considered with near field approximations and are easily obstructed by everyday objects. The need for near-field propagation considerations has thus given rise to a new range of techniques and solutions for mobile communications, one of which is the Airy beam.

The Airy Beam is a beam defined by the 2D Airy function, a function that satisfies the paraxial wave equation. The 2D Airy beam can be generated by modulating an incident beam with a cubic phase in frequency space, before transforming it into spatial coordinates. The resultant beam is self-accelerating and travels along a parabolic-shaped path. The curved and parabolic propagation path of the airy beam is a natural solution to the issue of Terahertz beams being easily obstructed. Furthermore, an Airy beam is self-healing, and any blockage in its propagation path can be recovered as it continues to propagate, a result of the properties of the Airy function.

Our research will revolve around the design and fabrication of Diffractive Optical Elements to generate Airy beams from a 0.3 THz incident beam. The first diffractive optical element will be a cubic phase plate to modulate the phase, and the second a Fresnel zone plate to transform the beam from frequency to spatial coordinates. Finally, the two will be combined into a single integrated phase plate. Results from both approaches will be compared, allowing for further characterization and insight into new methods of propagating Terahertz beams in wireless applications.