Project title: “Terahertz structured beams for material diagnostics and microscopy” – POIR.04.04.00-00-5E4E/18-00
Beneficiary: Warsaw Univeristy of Technology, Faculty of Physics
Funding value: 784 970 PLN
Project goal: Application of terahertz structured beams to improve the resolution of terahertz scanners

The new generation of higher resolution terahertz scanners

The absorption bands of almost all explosives are in terahertz radiation range, which makes it very effective in detecting them. Nowadays terahertz scanners have become increasingly important in counteracting terrorist threats – they are enabled to detect not allowed items for example carried by travellers at airports. However, commercially available terahertz scanners cannot achieve as high resolution as X-ray scanners, due to much longer terahertz wavelength. For this reason the images from terahertz scanners are blurry and not very detailed. Krzysztof Świtkowski, PhD, from the Faculty of Physics of the Warsaw University of Technology is working on improving the resolution of terahertz imaging.

Main objectives of the project

  • Generate THz vortex beam by two kinds of innovative methods
    • Direct optical generation of THz beams (optical vortex to THz conversion)
    • Generation of THz vortex beams by phase modulation of the Gaussian THz beam
  • Characterize spatial parameters of the resultant vortex beams
  • Study application potential of terahertz vortex beams with emphasis on techniques in which the smallest focused spot of the beam is important
  • Demonstrate the effect of vortex beams on the spatial resolution of “proof of concept” terahertz scanner and on the spatial resolution of near-fields terahertz microscope

The expected outcome of the project:

  • advance understanding of the properties (such as stability of higher charge vortices) of structured THz beams propagating in mediums and optical systems,
  • determination of the most efficient and practically suitable method for formation of high quality THz structured beams including vortices, and radially polarized vector beams which allow significant reduction of the focal spots below the diffraction limit of the Gaussian beam. The generated THz vector beams will be used to demonstrate the significantly improved spatial resolution in THz imaging (crucial for applications in THz object scanners and THz near-field microscopes).