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Frequency-tunable continuous-wave random lasers at terahertz frequencies

Random lasers are a class of devices in which feedback arises from multiple elastic scattering in a highly disordered structure, providing an almost ideal light source for artefact-free imaging due to achievable low spatial coherence. However, for many applications ranging from sensing and spectrosc...

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Detalles Bibliográficos
Autores principales: Biasco, Simone, Beere, Harvey E., Ritchie, David A., Li, Lianhe, Davies, A. Giles, Linfield, Edmund H., Vitiello, Miriam S.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6491491/
https://www.ncbi.nlm.nih.gov/pubmed/31044073
http://dx.doi.org/10.1038/s41377-019-0152-z
Descripción
Sumario:Random lasers are a class of devices in which feedback arises from multiple elastic scattering in a highly disordered structure, providing an almost ideal light source for artefact-free imaging due to achievable low spatial coherence. However, for many applications ranging from sensing and spectroscopy to speckle-free imaging, it is essential to have high-radiance sources operating in continuous-wave (CW). In this paper, we demonstrate CW operation of a random laser using an electrically pumped quantum-cascade laser gain medium in which a bi-dimensional (2D) random distribution of air holes is patterned into the top metal waveguide. We obtain a highly collimated vertical emission at ~3 THz, with a 430 GHz bandwidth, device operation up to 110 K, peak (pulsed) power of 21 mW, and CW emission of 1.7 mW. Furthermore, we show that an external cavity formed with a movable mirror can be used to tune a random laser, obtaining continuous frequency tuning over 11 GHz.