System and method for terahertz polarization-division multiplexing

1. A THz waveguide, comprising four conductive wires separated by an air gap, the THz waveguide allowing low-loss and dispersion-free propagation of a THz signal, wherein, depending on a polarization state of an excitation source, fundamental transverse electromagnetic modes TEMx and TEMy are excited within the waveguide, by a horizontally polarized THz beam and a vertically polarized THz beam respectively, and the waveguide independently guides THz multiplexed signals.

2. The THz waveguide of claim 1 , allowing low-loss and dispersion-free propagation of a broadband THz signal in a range between 0.1 THz and 3.0 THz.

3. The THz waveguide of claim 1 , wherein at least one of: i) a diameter of the wires; and ii) the air gap, is selected according to a target bandwidth of a THz signal propagating through the waveguide.

4. The THz waveguide of claim 1 , wherein at least one of: i) a diameter of the wires; and ii) the air gap, is selected according to a target loss of the waveguide.

5. The THz waveguide of claim 1 , wherein the air gap is selected according to a target loss of the waveguide.

6. The THz waveguide of claim 1 , wherein the wires are metallic wires.

7. The THz waveguide of claim 1 , comprising multiscale-structured grooves along the wires.

8. A THz waveguide, comprising four conductive wires separated by an air gap, the THz waveguide allowing low-loss and dispersion-free propagation of a THz signal, wherein, depending on a polarization state of an excitation source, fundamental transverse electromagnetic modes TEMx and TEMy are excited within the waveguide, by a horizontally polarized THz beam and a vertically polarized THz beam respectively, and the fundamental transverse electromagnetic modes transmit two broadband THz signals with orthogonal polarization states independently, the four-wire waveguide operating as a broadband polarization-division multiplexer.

9. A THz waveguide, comprising four conductive wires separated by an air gap, the THz waveguide allowing low-loss and dispersion-free propagation of a THz signal, wherein, depending on a polarization state of an excitation source, fundamental transverse electromagnetic modes TEMx and TEMy are excited within the waveguide, by a horizontally polarized THz beam and a vertically polarized THz beam respectively, a THz beam coupled into the waveguide with arbitrary polarization directions being decomposed into the fundamental transverse electromagnetic modes TEMx and TEMy of the waveguide, and propagating independently along the waveguide according to the two fundamental modes.

10. A system for terahertz polarization-division multiplexing, comprising at least two THz sources; a THz waveguide and a THz receiver, wherein said THz waveguide comprises four conductive wires separated by an air gap; THz pulses from the THz sources being coupled into the THz waveguide; wherein, depending on a polarization state of an excitation source, fundamental transverse electromagnetic modes TEMx and TEMy are excited within the waveguide, by a horizontally polarized THz beam and a vertically polarized THz beam respectively, and the fundamental transverse electromagnetic modes transmit two broadband THz signals with orthogonal polarization states independently, the four-wire waveguide operating as a broadband polarization-division multiplexer.

11. The system of claim 10 , wherein said THz sources comprise THz photoconductive antennas excited with femtosecond pulses.

12. The system of claim 10 , wherein said THz receiver comprises a ZnTe crystal.

13. The system of claim 10 , wherein at least one: i) a diameter of the wires and ii) the air gap, is selected according to at least one of: i) a target bandwidth of THz signals propagating through the THz waveguide, and ii) a target loss of the THz waveguide.

14. The system of claim 10 , wherein the wires are metallic wires.

15. The system of claim 10 , wherein said THz waveguide is engraved with multiscale-structured grooves along the wires thereof.

16. A method for terahertz polarization-division multiplexing, comprising multiplexing THz pulses from terahertz sources in free-space, coupling resulting multiplexed THz pulses into a THz waveguide comprising four conductive wires separated by an air gap; and demultiplexing the multiplexed THz pulses after propagation in the waveguide, wherein, depending on a polarization state of an excitation source, fundamental transverse electromagnetic modes TEMx and TEMy are excited within the waveguide, by a horizontally polarized THz beam and a vertically polarized THz beam respectively, and the fundamental transverse electromagnetic modes transmit two broadband THz signals with orthogonal polarization states independently, the four-wire waveguide operating as a broadband polarization-division multiplexer.

17. The method of claim 16 , comprising selecting at least one: i) a diameter of the wires and ii) the air gap, according to at least one of: i) a target bandwidth of THz signals propagating through the THz waveguide, and ii) a target loss of the THz waveguide.

18. The method of claim 16 , comprising providing multiscale-structured grooves along the wires of the waveguide.

19. The method of claim 16 , comprising independent manipulation of the multiplexed THz signals by integrating multiscale-structured grooves into the waveguide.