Direct intensity sampling of a modelocked terahertz quantum cascade laser

Maysonnave, Jean; Freeman, Joshua R.; Jukam, Nathan; Cavalié, P.; Maussang, Kenneth; Beere, Harvey E.; Ritchie, D. A.; Mangeney, J.; Dhillon, Sukhdeep; Tignon, Jérôme

doi:10.1063/1.4765660

Cited by 31 publications

(29 citation statements)

References 21 publications

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“…Finally, we checked that our model could robustly reproduce active mode-locking with the generation of picosecond pulses, as experimentally verified [5,6,9,12]. To this purpose we applied a strong current modulation at the round trip frequency ω M to a short cavity section.…”

Section: Active Mode-lockingmentioning

confidence: 99%

Dynamics of a broad-band quantum cascade laser: from chaos to coherent dynamics and mode-locking

Columbo¹,

Barbieri²,

Sirtori³

et al. 2018

Opt. Express

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Abstract:The dynamics of a multimode Quantum Cascade Laser, is studied in a model based on effective semiconductor Maxwell-Bloch equations, encompassing key features for the radiationmedium interaction such as an asymmetric, frequency dependent, gain and refractive index as well as the phase-amplitude coupling provided by the Henry factor. By considering the role of the free spectral range and Henry factor, we develop criteria suitable to identify the conditions which allow to destabilize, close to threshold, the traveling wave emitted by the laser and lead to chaotic or regular multimode dynamics. In the latter case our simulations show that the field oscillations are associated to self-confined structures which travel along the laser cavity, bridging mode-locking and solitary wave propagation. In addition, we show how a RF modulation of the bias current leads to active mode-locking yielding high-contrast, picosecond pulses. Our results compare well with recent experiments on broad-band THz-QCLs and may help understanding the conditions for the generation of ultrashort pulses and comb operation in Mid-IR and THz spectral regions.

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Section: Active Mode-lockingmentioning

confidence: 99%

Dynamics of a broad-band quantum cascade laser: from chaos to coherent dynamics and mode-locking

Columbo¹,

Barbieri²,

Sirtori³

et al. 2018

Opt. Express

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“…Finally, mode-locking was also achieved in the THz region by a combination of injection seeding and RF gain switching [49,50]. In the latter case, in contrast to the conventional mode-locking by RF injection, the phase of the THz pulse is fixed by seeding the THz QCL laser with the output of a gated photoconductive antenna.…”

Section: Mode-locking Of Qclsmentioning

confidence: 99%

“…This second coherence property is linked to the comb offset frequency fceo. , PDI [73], Harvard [37], ENS [50], MIT [70].…”

Section: Comb Coherencementioning

confidence: 99%

Quantum Cascade Laser Frequency Combs

Faist

Villares²,

Scalari³

et al. 2016

Nanophotonics

189

137

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It was recently demonstrated that broadband quantum cascade lasers can operate as frequency combs. As such, they operate under direct electrical pumping at both mid-infrared and THz frequencies, making them very attractive for dual-comb spectroscopy. Performance levels are continuously improving, with average powers over 100 mW and frequency coverage of 100 cm −1 in the midinfrared region. In the THz range, 10 mW of average power and 600 GHz of frequency coverage are reported. As a result of the very short upper state lifetime of the gain medium, the mode proliferation in these sources arises from four-wave mixing rather than saturable absorption. As a result, their optical output is characterized by the tendency of small intensity modulation of the output power, and the relative phases of the modes to be similar to the ones of a frequency modulated laser. Recent results include the proof of comb operation down to a metrological level, the observation of a Schawlow-Townes broadened linewidth, as well as the first dual-comb spectroscopy measurements. The capability of the structure to integrate monothically nonlinear optical elements as well as to operate as a detector shows great promise for future chip integration of dual-comb systems.

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“…In recent years active modelocking of a terahertz (THz) quantum cascade laser (QCLs) has been reported [1,2]. However, it is difficult to form stable modelocked pulses from this type of device owing to the interplay of the inherent characteristic lifetimes, most notably the ratio of the gain recovery time (GRT) and round-trip time of the laser cavity.…”

Section: Introductionmentioning

confidence: 99%

Pump-probe measurements of gain in a terahertz quantum cascade laser

Bacon

Freeman

Mohandas

et al. 2016

2016 41st International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)

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-The gain recovery time of a bound-to-continuum terahertz frequency quantum cascade laser, operating at 1.98 THz, has been measured using broadband terahertz-pumpterahertz-probe spectroscopy. The recovery time is found to reduce as a function of current density, reaching a value of 18 ps as the laser is brought close to threshold. We attribute this reduction to improved coupling efficiency between the injector state and the upper lasing level as the active region aligns.

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Direct intensity sampling of a modelocked terahertz quantum cascade laser

Cited by 31 publications

References 21 publications

Dynamics of a broad-band quantum cascade laser: from chaos to coherent dynamics and mode-locking

Dynamics of a broad-band quantum cascade laser: from chaos to coherent dynamics and mode-locking

Quantum Cascade Laser Frequency Combs

Pump-probe measurements of gain in a terahertz quantum cascade laser

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