Low-duty-cycle continuous-wave photoconductive terahertz imaging and spectroscopy systems
View Patent ↗Systems and methods for plasmonics enhanced photomixing for generating continuous-wave (CW) frequency-tunable terahertz radiation in accordance with embodiments of the invention are disclosed. A photomixing system configured to generate continuous-wave terahertz frequency signals can include an optical pump configured to generate at least two beams, where the at least two beams are utilized to create a frequency-offset and operate below a 50% duty cycle, where the duty cycle includes an operation cycle and a sleep cycle. The photomixing system can also include a photomixer that includes a radiating element configured to receive the frequency-offset and to generate a terahertz radiation utilizing the received frequency-offset and the radiating element, where the radiating element includes at least one plasmonic contact electrode.
1. A photomixing system configured to generate continuous-wave terahertz frequency signals comprising:
an optical pump configured to:
generate at least two beams, where the at least two beams are utilized to create a frequency-offset; and
operate below a 50% duty cycle, where the duty cycle includes an operation cycle and a sleep cycle, wherein the optical pump operates with an average optical pump power of less than or equal to 150 mW; and
a photomixer comprising a radiating element configured to receive the frequency-offset and to generate a terahertz radiation utilizing the received frequency-offset and the radiating element, wherein the radiating element includes at least one plasmonic contact electrode.
2. The photomixing system of claim 1 , wherein the radiating element is an antenna capable of broadband radiation.
3. The photomixing system of claim 2 , wherein the radiating element is selected from the group consisting of a logarithmic spiral antenna, a dipole antenna, a bow-tie antenna, a log-periodic antenna, and a folded dipole antenna.
4. The photomixing system of claim 1 , wherein the photomixer is fabricated on a substrate that is capable of absorbing photons in the optical pump's operating wavelength range.
5. The photomixing system of claim 4 , wherein the photomixer is fabricated on an ErAs compound substrate.
6. The photomixing system of claim 4 , wherein the photomixer is fabricated on an InGaAs compound substrate.
7. The photomixing system of claim 4 , wherein the photomixer is fabricated on a substrate selected from the group consisting of GaAs, InGaAs, Ge, InP, Graphene, and GaN substrates.
8. The photomixing system of claim 1 , wherein the generated terahertz radiation has a 0.25-2.5 THz frequency range.
9. The photomixing system of claim 1 , wherein the generated terahertz radiation has a frequency range greater than 2.5 THz.
10. The photomixing system of claim 1 , wherein the generated terahertz radiation has a frequency range less than 0.25 THz.
11. The photomixing system of claim 1 , wherein the generated terahertz radiation is frequency-tunable.
12. The photomixing system of claim 1 , wherein the generated terahertz radiation is a non-tunable radiation.
13. A method for generating continuous-wave terahertz frequency signals using a photomixing system comprising:
generating at least two beams using an optical pump, where the at least two beams are utilized to create a frequency-offset; operating the optical pump below a 50% duty cycle, where the duty cycle includes an operation cycle and a sleep cycle, wherein the optical pump operates with an average optical pump power of less than or equal to 150 mW;
receiving the frequency-offset using a photomixer, where the photomixer comprises a radiating element, wherein the radiating element includes at least one plasmonic contact electrode; and
generating a terahertz radiation based upon the received frequency-offset and the radiating element.
14. The method of claim 13 , wherein the radiating element is an antenna capable of broadband radiation.
15. The method of claim 14 , wherein the radiating element is selected from the group consisting of a logarithmic spiral antenna, a dipole antenna, a bow-tie antenna, a log-periodic antenna, and a folded dipole antenna.
16. The method of claim 13 , wherein the photomixer is fabricated on a substrate that is capable of absorbing photons in the optical pump's operating wavelength range.
17. The method of claim 16 , wherein the photomixer is fabricated on an ErAs compound substrate.
18. The method of claim 16 , wherein the photomixer is fabricated on an InGaAs compound substrate.
19. The method of system of claim 16 , wherein the photomixer is fabricated on a substrate selected from the group consisting of GaAs, InGaAs, Ge, InP, Graphene, and GaN substrates.
20. The method of claim 13 , wherein the generated terahertz radiation has a 0.25-2.5 THz frequency range.
21. The method of claim 13 , wherein the generated terahertz radiation has a frequency range greater than 2.5 THz.
22. The method of claim 13 , wherein the generated terahertz radiation has a frequency range less than 0.25 THz.
23. The method of claim 13 , wherein the generated terahertz radiation is frequency-tunable.
24. The method of claim 13 , wherein the generated terahertz radiation is a non-tunable radiation.