Abstract-Coupled-cavity terahertz quantum cascade lasers for single mode operation

H. Li^1,a), J. M. Manceau^1,b), A. Andronico¹, V. Jagtap¹, C. Sirtori¹, L. H. Li²,E. H. Linfield², A. G. ² and S. Barbieri^1,c)

 HIDE AFFILIATIONS
1 Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Diderot and CNRS, UMR 7162, 10 rue A. Domont et L. Duquet, 75205 Paris, France
2 School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
a) Electronic mail: hua.li@univ-paris-diderot.fr
b) Present address: Institut d'Electronique Fondamentale, Université Paris Sud and CNRS, UMR 8622, 91405 Orsay, France
c) Electronic mail: stefano.barbieri@univ-paris-diderot.fr
Appl. Phys. Lett. 104, 241102 (2014); http://dx.doi.org/10.1063/1.4884056
http://scitation.aip.org/content/aip/journal/apl/104/24/10.1063/1.4884056
We demonstrate the operation of coupled-cavity terahertz frequency quantum-cascade lasers composed of two sub-cavities separated by an air gap realized by optical lithography and dryetching. This geometry allows stable, single mode operation with typical side mode suppression ratios in the 30–40 dB range. We employ a transfer matrix method to model the mode selection mechanism. The obtained results are in good agreement with the measurements and allow prediction of the operating frequency.