Time-Resolved Investigations of Electronic Transport Dynamics in Quantum Cascade Lasers Based on Diagonal Lasing Transition

Choi, Hyung-Jin; Diehl, Laurent; Wu, Zhiyuan; Giovannini, Marcella; Faist, Jérôme; Capasso, Federico; Norris, Theodore B.

doi:10.1109/jqe.2009.2013091

Cited by 16 publications

(7 citation statements)

References 45 publications

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“…(17), we use our measured values of T 2 but still need an estimate for the gain recovery time T 1 . Pump-probe experiments [62,63] and theory [64] have shown that T 1 is around 2 ps. From Eq.…”

Section: Discussionmentioning

confidence: 99%

“…The resulting curves are shown in Fig. 12, and a summary of all input and output parameters is given in [62,63] and theory [64] to be around 2 ps. However, the predicted p sb is significantly lower than the measured values J sb /J th = 1.12 (DS-3.8), 1.17 (TL-4.6), and 1.14 (LL-9.8), and the discrepancy is made worse by the fact that J /J th is likely an underestimate of p (see the discussion in Appendix A).…”

Section: Appendix H: Comparison Of Theory and Datamentioning

confidence: 99%

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Single-mode instability in standing-wave lasers: The quantum cascade laser as a self-pumped parametric oscillator

et al. 2016

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We report the observation of a clear single-mode instability threshold in continuous-wave Fabry-Perot quantum cascade lasers (QCLs). The instability is characterized by the appearance of sidebands separated by tens of free spectral ranges (FSR) from the first lasing mode, at a pump current not much higher than the lasing threshold. As the current is increased, higher-order sidebands appear that preserve the initial spacing, and the spectra are suggestive of harmonically phase-locked waveforms. We present a theory of the instability that applies to all homogeneously broadened standing-wave lasers. The low instability threshold and the large sideband spacing can be explained by the combination of an unclamped, incoherent Lorentzian gain due to the population grating, and a coherent parametric gain caused by temporal population pulsations that changes the spectral gain line shape. The parametric term suppresses the gain of sidebands whose separation is much smaller than the reciprocal gain recovery time, while enhancing the gain of more distant sidebands. The large gain recovery frequency of the QCL compared to the FSR is essential to observe this parametric effect, which is responsible for the multiple-FSR sideband separation. We predict that by tuning the strength of the incoherent gain contribution, for example by engineering the modal overlap factors and the carrier diffusion, both amplitude-modulated (AM) or frequency-modulated emission can be achieved from QCLs. We provide initial evidence of an AM waveform emitted by a QCL with highly asymmetric facet reflectivities, thereby opening a promising route to ultrashort pulse generation in the mid-infrared. Together, the experiments and theory clarify a deep connection between parametric oscillation in optically pumped microresonators and the single-mode instability of lasers, tying together literature from the last 60 years.

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Section: Discussionmentioning

confidence: 99%

Section: Appendix H: Comparison Of Theory and Datamentioning

confidence: 99%

Single-mode instability in standing-wave lasers: The quantum cascade laser as a self-pumped parametric oscillator

et al. 2016

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“…Furthermore, quantum cascade lasers can generate THz radiation 51 . Semiconductor nanostructures used in such devices have very high dipole moments (tens of Debye) and can operate as three-level systems 52 , 53 . In some media like crystals, containing impurities of rare-earth ions, the values of at low temperatures can approach extremely high values - from several seconds to several hours 54 .…”

Section: Introductionmentioning

confidence: 99%

Population difference gratings created on vibrational transitions by nonoverlapping subcycle THz pulses

Архипов

Пахомов

Архипов

et al. 2021

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We study theoretically a possibility of creation and ultrafast control (erasing, spatial frequency multiplication) of population density gratings in a multi-level resonant medium having a resonance transition frequency in the THz range. These gratings are produced by subcycle THz pulses coherently interacting with a nonlinear medium, without any need for pulses to overlap, thereby utilizing an indirect pulse interaction via an induced coherent polarization grating. High values of dipole moments of the transitions in the THz range facilitate low field strength of the needed THz excitation. Our results clearly show this possibility in multi-level resonant media. Our theoretical approach is based on an approximate analytical solution of time-dependent Schrödinger equation (TDSE) using perturbation theory. Remarkably, as we show here, quasi-unipolar subcycle pulses allow more efficient excitation of higher quantum levels, leading to gratings with a stronger modulation depth. Numerical simulations, performed for THz resonances of the $$H_20$$ H 2 0 molecule using Bloch equations for density matrix elements, are in agreement with analytical results in the perturbative regime. In the strong-field non-perturbative regime, the spatial shape of the gratings becomes non-harmonic. A possibility of THz radiation control using such gratings is discussed. The predicted phenomena open novel avenues in THz spectroscopy of molecules with unipolar and quasi-unipolar THz light bursts and allow for better control of ultra-short THz pulses.

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“…During lasing, the voltage across the cascade remains clamped at V th because the current is driven by stimulated emission of [10].…”

Section: Electro-optical Energy Conversion In Mir Quantum Cascade Lasersmentioning

confidence: 99%

Modeling the Electro-Optical Performance of High Power Mid-Infrared Quantum Cascade Lasers

2016

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Performance modeling of the characteristics of mid-infrared quantum cascade lasers (MIR QCL) is an essential element in formulating consistent component requirements and specifications, in preparing guidelines for the design and manufacture of the QCL structures, and in assessing different modes of operation of the laser device. We use principles of system physics to analyze the electro-optical characteristics of high power MIR QCL, including thermal backfilling of the lower laser level, hot electron effects, and Stark detuning during lasing. The analysis is based on analytical modeling to give simple mathematical expressions which are easily incorporated in system-level simulations of defense applications such as directed infrared countermeasures (DIRCM). The paper delineates the system physics of the electro-optical energy conversion in QCL and the related modeling. The application of the performance model to a DIRCM QCL is explained by an example.

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Time-Resolved Investigations of Electronic Transport Dynamics in Quantum Cascade Lasers Based on Diagonal Lasing Transition

Cited by 16 publications

References 45 publications

Single-mode instability in standing-wave lasers: The quantum cascade laser as a self-pumped parametric oscillator

Single-mode instability in standing-wave lasers: The quantum cascade laser as a self-pumped parametric oscillator

Population difference gratings created on vibrational transitions by nonoverlapping subcycle THz pulses

Modeling the Electro-Optical Performance of High Power Mid-Infrared Quantum Cascade Lasers

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