We present a monolithic solution to extract efficiently light from terahertz quantum cascade lasers with metal-metal waveguides suitable for broadband frequency comb applications. The design is optimized for a bandwidth of 400 GHz around a center frequency of 2.5 THz. A five-fold increase in total output power is observed compared to standard metal-metal waveguides. The extractor features a single-lobed far-field pattern and increases the frequency comb dynamical range to cover more than 50% of the laser dynamic range. Frequency comb operation up to a spectral bandwidth of 670 GHz is achieved.
Broadband monolithic extractor for metal-metal waveguide based terahertz quantum cascade laser frequency combs
Markus Rösch, Ileana-Cristina Benea-Chelmus, Christopher Bonzon, Martin J. Süess, Mattias Beck, Jérôme Faist, Giacomo Scalari; Broadband monolithic extractor for metal-metal waveguide based terahertz quantum cascade laser frequency combs. Appl. Phys. Lett. 10 July 2017; 111 (2): 021106. https://doi.org/10.1063/1.4993786
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