Upscaling the output power of a photo-mixing THz source driven by a dual-frequency laser operating on two transverse modes

摘要

The use of photo-mixing techniques for THz emission ou000bers attractive performances such as tunability and modulationbandwidth, that are suitable for bio-medical sensing and imaging, communications, or security. We willpresent the state-of-the-art performances of a vertical-external-cavity surface-emitting laser that operates ontwo 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-carrierphotodiode (UTC-PD). The stability of the dual-frequency operation is achieved thanks to diu000berent types offunctionalized surfaces involving the micro-fabrication of integrated Ⅲ-Ⅴ absorbing metallic masks or metamaterialphase masks by e-beam lithography. These functionalized surfaces allow to shape the optical and THzperformances in terms of power, tunability and coherence. The latter will be specically detailed in terms oflongitudinal coherence, showing a THz frequency noise that is orders of magnitude lower than the optical onethanks to a signicant correlation of technical noise. Tunable emission will be demonstrated from 50 GHz upto few THz with a linewidth of 150 kHz (during 3-ms), for a power of 1 W at 260 GHz that is limited by theUTC-PD for an optical excitation at 1064 nm at room temperature. We will discuss on the possibility to improvesuch a power signicantly by taking advantage of the involved high-order transverse mode, ou000bering possible intrinsicallycoherent networks of photo-emitters, thus paving the way to compact and agile coherent THz sourcesou000bering an output power over few mWs at frequencies of 100s of GHz.