Mikhaël Myara, Baptiste Chomet, Alaeddine Abbes, Arnaud Garnache, Stéphane Blin, Grégoire Beaudoin, Isabelle Sagnes
https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10926/109261E/Upscaling-the-output-power-of-a-photo-mixing-THz-source/10.1117/12.2514721.short?SSO=1
The use of photo-mixing techniques for THz
emission offers attractive performances such as tunability and modulation
bandwidth, that are suitable for bio-medical sensing and imaging,
communications, or security. We will present the state-of-the-art performances
of a vertical-external-cavity surface-emitting laser that operates on two
transverse modes to ensure a stable continuous-wave and coherent (longitudinal,
transverse and polarization) dual-frequency operation. THz emission is
subsequently obtained by excitation of an uni-traveling-carrier photodiode
(UTC-PD). The stability of the dual-frequency operation is achieved thanks to
different types of functionalized surfaces involving the micro-fabrication of
integrated III-V absorbing metallic masks or metamaterial phase masks by e-beam
lithography. These functionalized surfaces allow to shape the optical and THz
performances in terms of power, tunability and coherence. The latter will be
specifically detailed in terms of longitudinal coherence, showing a THz
frequency noise that is orders of magnitude lower than the optical one thanks
to a significant correlation of technical noise. Tunable emission will be
demonstrated from 50 GHz up to few THz with a linewidth of 150 kHz (during
3-ms), for a power of 1 W at 260 GHz that is limited by the UTC-PD for an
optical excitation at 1064 nm at room temperature. We will discuss on the
possibility to improve such a power significantly by taking advantage of the
involved high-order transverse mode, offering possible intrinsically coherent
networks of photo-emitters, thus paving the way to compact and agile coherent
THz sources offering an output power over few mWs at frequencies of 100s of GHz.
