Multi-pixel photoconductive emitters for the controllable generation of azimuthal and radial terahertz beams

A multi-pixel photoconductive emitter is reported that generates THz beams with either azimuthal, radial or linear polarization states. Switching between the different polarization states was purely electrical, via the bias voltage applied, circumventing the need for mechanical polarization optics or different THz emitters to change the polarization. Dipole array modelling was performed to validate emitter array designs, and to explore their optimal bias configuration, while spatially-resolved electro-optic detection of the generated beams confirmed that cylindrical-vector beams were produced. We further demonstrate that the spatial beam profile was optimized by adjusting the bias level on particular pixels, improving the polarization purity of the beam. Published by Optica Publishing Group under the terms of the Creative Commons Attribution 4.0 License.

Automated summary

A multi-pixel photoconductive emitter is reported that can generate THz beams with various polarization states by purely electrical switching, without the need for mechanical polarization optics or different THz emitters. Dipole array modeling and spatially-resolved electro-optic detection confirmed the production and optimization of cylindrical-vector beams.