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Narrow linewidth THz generation using a cascaded Brillouin fibre laser structure and a unitraveling carrier photodiode is proposed. Using two distributed feedback lasers separated by > 1 THz with 1 MHz initial linewidth, the linewidth of the realized THz source is found to be < 100 Hz at 1014.7 GHz without use of any active stabilization of the laser cavity or any microwave reference.
A TEM horn antenna is integrated with a uni-travelling-carrier photodiode. Its radiation pattern is measured from 280 to 540 GHz thanks to a 1.55 μm photomixing set-up and a sub-harmonic mixer. The direction the main lobe shifts to a lower incidence when the frequency is increased.
Quantum Cascade Lasers (QCL) are probably the most promising sources for Terahertz wave generation. The key issue especially for double metal QCLs is the extraction and the beam shaping of the emitted power. We propose a solution with a TEM-Horn Antenna and we compare it to the most recently proposed solutions: plasmonic array, Silicon-lens etc. New Terahertz antenna designs will also be presented.
We present the operation and the far field radiation pattern of a 2.9 THz double metal quantum cascade laser (QCL) with a micro TEM-horn antenna. An improvement of both the radiation pattern and the collected power level (typically a factor of 2 with f/1 optics) are observed in comparison with the QCL without antenna.
A horn-antenna is integrated on a microstrip waveguide QCL emitting at 2.0 THz. This allows a better impedance match to free space, which improves substantially the directivity of the beam and the radiation outcoupling.
Quantum Cascade Lasers are one the most promising approach for the generation of THz waves and particularly in a double plasmon waveguide topology. Stripline resonators with a quasi-TEM mode are indeed interesting for THz-QCLs thanks to a high confinement factor combined with low losses. However they present two major drawbacks: the first is a poor outcoupling of the radiation, and the second is a...
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