Coupling terahertz radiation between sub-wavelength metal-metal waveguides and free space using monolithically integrated horn antennae.
Broadband horn antennae are presented that efficiently couple terahertz radiation between sub-wavelength metal-metal waveguides and free space. Sub-picosecond terahertz pulses were coupled into and out from sub-wavelength parallel-plate waveguides by using the horn antennae in a terahertz time-domain spectrometer. Monolithic antennae were fabricated at the facets of metal-metal terahertz quantum cascade lasers, and laser action was observed for devices emitting at 1.4 THz, 2.3 THz and 3.2 THz. A good far-field laser radiation pattern (FWHM less than 11 degrees) is obtained as a result of the significant expansion of the optical mode by the antenna.
Lloyd-Hughes
J
J
Institute for Quantum Electronics, ETH Zurich, 8092 Zurich, Switzerland.
Scalari
G
G
van Kolck
A
A
Fischer
M
M
Beck
M
M
Faist
J
J
D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008027:Light; D008670:Metals / Q000737:chemistry*; D012031:Refractometry / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D055053:Terahertz Radiation; D055068:Terahertz Spectroscopy / Q000295:instrumentation* / Q000379:methods*
D008670:Metals