Terahertz generation in quantum-cascade lasers through down-conversion optical nonlinearity: Design and modeling

Kazemi-Tesieh, Mohammad Reza; Yousefvand, Hossein Reza; Ghadimi, Abbas; Kiani-Sarkaleh, Azadeh

doi:10.1016/j.optcom.2020.125792

Cited by 6 publications

(17 citation statements)

References 42 publications

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“…We employ scattering mechanism calculation that is described in detail in [39] we use equithermal subband approximation for solving the kinetic balance equation and obtaining the electron temperature. This approach [30,44] transforms the kinetic balance equation into a minimization problem with one unknown, rather than the nonlinear system [37,45] with subband temperatures as the unknowns. Therefore our model consists of iterative algorithm (the Schrödinger-Poission solver) nested within the minimization algorithm for determination of electron temperature.…”

Section: Cut-off Temperature Predictionmentioning

confidence: 99%

Prospects of temperature performance enhancement through higher resonant phonon transition designs in GaAs-based terahertz quantum-cascade lasers

et al. 2022

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In this work we discuss terahertz quantum cascade laser designs that employ resonant phonon mechanism to assist the lasing process. We investigate whether the higher energy separation would be more beneficial for high temperature performance than commonly used resonant value of 36 meV (in GaAs). We show that our density matrix model can be used for reliable cut–off temperature estimation and we present design improvement of several exemplary structures by enhancing their material gain to attain 10 - 50 K higher cut–off temperature

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Section: Cut-off Temperature Predictionmentioning

confidence: 99%

Prospects of temperature performance enhancement through higher resonant phonon transition designs in GaAs-based terahertz quantum-cascade lasers

et al. 2022

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“…In the previous studies [14,15], with a combination of mid-IR QCLs and frequency-down conversion optical nonlinearity, we have proposed two distinct active region designs to generate THz radiation at room temperature. In the current study, a mid-IR QCL is integrated with a four-level Raman-type system to achieve THz lasing without the need for population inversion.…”

Section: Introductionmentioning

confidence: 99%

“…In the current study, a mid-IR QCL is integrated with a four-level Raman-type system to achieve THz lasing without the need for population inversion. In contrast to the previous works [14,15], in which the nonlinear THz region has a smaller conduction band offset as compared to the mid-IR pump region, both the mid-IR pump region and THz nonlinear region in the current study are constructed from the Al 0.32 Ga 0.68 As/GaAs material system with same band offset energy. Similar to our previous study [14,15], the proposed design has the added advantage that no phase matching is required, because the THz photon energy is not derived from the mid-IR photon energy [11], but comes from the external electrical bias.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast to the previous works [14,15], in which the nonlinear THz region has a smaller conduction band offset as compared to the mid-IR pump region, both the mid-IR pump region and THz nonlinear region in the current study are constructed from the Al 0.32 Ga 0.68 As/GaAs material system with same band offset energy. Similar to our previous study [14,15], the proposed design has the added advantage that no phase matching is required, because the THz photon energy is not derived from the mid-IR photon energy [11], but comes from the external electrical bias. In this paper, the basic idea is to use a mid-IR QCL as an intracavity optical pump with less temperature-dependent characteristics for producing THz transition via quantum coherence effects (lasing without inversion).…”

Section: Introductionmentioning

confidence: 99%

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Inversionless terahertz lasing in a four-level Raman-type scheme within mid-infrared quantum cascade structures

et al. 2023

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This paper applies the density matrix formalism to investigate a feasibility of inversionless terahertz (THz) lasing within a mid-infrared (mid-IR) quantum cascade laser (QCL). The proposed structure aims to use a mid-IR QCL as an efficient pump source that integrated with a four-level Raman-type scheme to generate THz radiation through strong coherence excited in the system. A key aspect of the design is that the THz generation is achieved by interplay between inversion-based lasing and coherent effects due to quantum interference between the microscopic polarizations of the dipole-allowed transitions in the four-level system. THz intensity gain arising from both the inversion-based lasing and coherent effects is derived from the off-diagonal density matrix elements in the four-level system. The simulation results indicate that the proposed design demonstrates the potential to achieve THz lasing with good temperature characteristics and without the need for population inversion.

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“…Due to the presence of atmospheric inhomogeneities like aerosols that lead to molecular absorption, the received optical power fluctuates leading to a high bit error rate (BER) [16]. Other notable designs of QCLs are found in [17,18]. The QWIP reported in [19,20] is the receiver used in the link design since it provides a good performance in the wavelength of interest.…”

Section: Introductionmentioning

confidence: 99%

Performance evaluation of free space optical link driven by gain switched temperature dependent quantum cascade lasers

Gopinath¹,

Ashok²,

Madhan³

2021

Laser Phys. Lett.

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Temperature dependent terahertz frequency quantum cascade lasers (QCLs) offer huge potential in a large number of new applications. Reduced rate equations are used for better understanding of their behavior and to predict the optical output power under changing current drive and chip temperature. This letter reports the complete end-to-end free space optical (FSO) link driven by a gain switched temperature dependent QCL as transmitter. The device used in the FSO link consists of 90 periods of injector and active regions, emitting light at 116 µm. The device is driven by various electrical inputs such as square, haversine and tangential hyperbolic pulses. The short pulses generated by gain switching travel 1500 m to reach the quantum well infrared photodetector operating in the same wavelength as the source. The performance parameters; namely signal-to-noise ratio (SNR), bit error rate (BER) and capacity are computed for the various input signals. Under the minimum full width half maximum condition, haversine input provides a better performance providing a BER of 7.8 × 10−5, with a peak SNR of 14.56 dB and a capacity of 4.89 bps Hz−1 at a cold finger temperature of 45 K. When peak power is the criterion, tangential hyperbolic input performs well with a minimum BER of 7.66 × 10−9, a peak SNR of 18.06 dB and a capacity of 6.02 bps Hz−1 at a cold finger temperature of 45 K.

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Terahertz generation in quantum-cascade lasers through down-conversion optical nonlinearity: Design and modeling

Cited by 6 publications

References 42 publications

Prospects of temperature performance enhancement through higher resonant phonon transition designs in GaAs-based terahertz quantum-cascade lasers

Prospects of temperature performance enhancement through higher resonant phonon transition designs in GaAs-based terahertz quantum-cascade lasers

Inversionless terahertz lasing in a four-level Raman-type scheme within mid-infrared quantum cascade structures

Performance evaluation of free space optical link driven by gain switched temperature dependent quantum cascade lasers

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