Room temperature continuous wave, monolithic tunable THz sources based on highly efficient mid-infrared quantum cascade lasers

• Published in: Scientific reports Vol. 6; no. 1; p. 23595
• Main Authors: Lu, Quanyong, Wu, Donghai, Sengupta, Saumya, Slivken, Steven, Razeghi, Manijeh
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 24.03.2016; Nature Publishing Group
• Subjects: 142/126; 639/624/1020/1092; 639/766/400/385; Emissions; Feedback; Humanities and Social Sciences; Lasers; Military communications; multidisciplinary; Science; Spectroscopy; Temperature effects
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep23595

A compact, high power, room temperature continuous wave terahertz source emitting in a wide frequency range (ν ~ 1–5 THz) is of great importance to terahertz system development for applications in spectroscopy, communication, sensing and imaging. Here, we present a strong-coupled strain-balanced quantum cascade laser design for efficient THz generation based on intracavity difference frequency generation. Room temperature continuous wave emission at 3.41 THz with a side-mode suppression ratio of 30 dB and output power up to 14 μW is achieved with a wall-plug efficiency about one order of magnitude higher than previous demonstrations. With this highly efficient design, continuous wave, single mode THz emissions with a wide frequency tuning range of 2.06–4.35 THz and an output power up to 4.2 μW are demonstrated at room temperature from two monolithic three-section sampled grating distributed feedback-distributed Bragg reflector lasers.