Abstract-High-Q resonant cavities for terahertz quantum cascade lasers

High-Q resonant cavities for terahertz quantum cascade lasers A. Campa, L. Consolino, M. Ravaro, D. Mazzotti, M. S. Vitiello, S. Bartalini, and P. De Natale  »View Author Affiliations http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-23-3-3751

Optics Express, Vol. 23, Issue 3, pp. 3751-3761 (2015)
http://dx.doi.org/10.1364/OE.23.003751

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We report on the realization and characterization of two different designs for resonant THz cavities, based on wire-grid polarizers as input/output couplers, and injected by a continuous-wave quantum cascade laser (QCL) emitting at 2.55 THz. A comparison between the measured resonators parameters and the expected theoretical values is reported. With achieved quality factor Q ≈ 2.5 × 10⁵, these cavities show resonant peaks as narrow as few MHz, comparable with the typical Doppler linewidth of THz molecular transitions and slightly broader than the free-running QCL emission spectrum. The effects of the optical feedback from one cavity to the QCL are examined by using the other cavity as a frequency reference.

© 2015 Optical Society of America