Recent Advances of Efficient Design of Terahertz Quantum-Cascade Lasers

Sharma, Rajesh; Kaur, Harpreet; Singh, Manjot

doi:10.1007/s11468-020-01295-4

Cited by 9 publications

(4 citation statements)

References 44 publications

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“…For instance, the degraded PI is also reported to originate primarily from thermal backfilling and slow extraction of electrons at the lower state rather than the increasing phonon emission rate at the upper state. [ 3,23–25 ] In another case, the parasitic leakage channel is speculated to have little impact on PI at high temperature since a small fraction of electrons reside at continuum levels according to calculations, [ 13 ] yielding inconsistent with other studies. [ 3,5 ] In addition, discrepancies often emerge between theoretical computations and experimental results.…”

Section: Introductionmentioning

confidence: 99%

Extraction‐Dominated Temperature Degradation of Population Inversion in Terahertz Quantum Cascade Lasers

Zhang

Zhao

et al. 2022

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be exploited during the THz QCL operation due to its rapid performance degradation at elevated temperature, [7] which has impeded its practical application in many areas, such as security, astrophysics, and medical treatment. To this date, while the most progressive THz QCL based on phonon-tunneling design could be operated at the maximum temperature of 250 K in pulse mode, [5] there exists a certain distance from room-temperature operation, and its luminous efficiency deteriorates rapidly at elevated temperatures. [1,8] Indeed, we are still far away from achieving high-output THz QCL at room temperature.Regarding this major challenge, numerous researches have been directed to investigating the temperature degradation phenomenon in THz QCL and several limiting factors have been identified accordingly, including degraded population inversion (PI), [9][10][11] reabsorption of broadened states, [12][13][14] and increased parasitic current density at elevated temperature. [3,15,16] Among these factors, the reduction of PI is the most concern, as the peak gain of a laser device is proportional to the degree of PI between its upper laser state and lower level state. In view of this, clarifying the mechanism of the degraded PI is an essential precondition to optimize the elevated temperature Degraded population inversion (PI) at elevated temperature, regarded as an important temperature degradation factor in terahertz quantum cascade lasers (THz QCL), has hindered the widespread use of these devices. Herein, the mechanism of the temperature degradation of PI is investigated microscopically. It is demonstrated that the limited extraction efficiency of the extraction system dominates the decrease of PI at elevated temperatures. To be specific, the increased temperature brings about intense thermally activated longitudinal optical phonon scattering, leading to large amounts of electrons scattering to lower level state. In this case, the resonant-phonon extraction system is incapable of depleting all the electrons from lower level states. So even though the resonant-tunneling injection seems efficient enough to compensate the electron runoff at the upper state, the electron density at lower level state increases and the overall PI turns out lower. In addition, it is found that strong electron-ionized donor separation at high temperature can induce level misalignment, which can stagger the optimal conditions of injection and extraction. Also, the extraction efficiency gets lower as the extraction system requires accurate coupling between several energy levels.

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Section: Introductionmentioning

confidence: 99%

Extraction‐Dominated Temperature Degradation of Population Inversion in Terahertz Quantum Cascade Lasers

Zhang

Zhao

et al. 2022

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“…NQCL employs quantum cascade effect within nanoscale structures to emit coherent light in the mid-infrared spectrum [1][2][3][4][5]. Nano QCLs are semiconductor-based devices that utilize transitions between quantized energy states in ultrathin layers to achieve photon emission [6][7][8][9][10]. A key advantage of Nano QCLs is their abilities to operate in the mid-infrared region, where numerous chemical compounds exhibit unique absorption characteristics.…”

Section: Introductionmentioning

confidence: 99%

Studying the Synchronization for Multiple Transmitter- Receiver Nano Quantum Cascade Lasers.

Resan,

Waried

2024

UTJsci

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In this paper, the chaos synchronization of four Nano quantum cascade lasers with optoelectronic feedback was investigated. The present system consists of two receiver lasers and two transmitters lasers. The rate equation model was modulated to study the effect of the Purcell factor F and the spontaneous emission factor because of their importance in a nanocavity. The results indicated that the suggested system, realize the chaos synchronization. Also, the nanocavity parameters F and β, have significant effect on the chaos synchronization quality and may lead to lose it. Furthermore, the results showed the weak effect of delay time on the performance of lasers.

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“…In the last few years, the application of terahertz technology in biosensing [1], spectroscopy [2,3] and imaging [4], wireless communication [5], as well as the detection and identification [6] has been rapidly developed, which is mainly because of the development of electronics, lasers and semiconductors [7]. Nevertheless, with the rapid development of terahertz technology, it also brings increasingly electromagnetic radiation in terahertz range.…”

Section: Introductionmentioning

confidence: 99%

Enhanced terahertz shielding by adding rare Ag nanoparticles to Ti₃C₂T _x MXene fiber membranes

Zou¹,

Shi²,

Liu³

et al. 2021

Nanotechnology

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Polyacrylonitrile/Ti3C2T x MXene/silver nanoparticles fiber membranes with different silver nanoparticles contents and thickness of porous structure have been successfully prepared by electrospinning. Through the measurement of terahertz time domain spectrum, the shielding effect of the fiber membrane with 1% silver nanoparticles content can reach up to 12 dB. Moreover, the thickness of the spinning fiber membranes is controlled by adjusting the spinning time, so as to better analyze the influence of the thickness of the shielding performance in terahertz band. We attribute this excellent phenomenon to porous structure of the spun fiber membrane and combination of Ti3C2T x MXene with few-layers and silver nanoparticles to increase the absorption and conductivity of the fiber membrane, thereby enhancing the shielding effect in terahertz range. Meanwhile, the prepared polyacrylonitrile/Ti3C2T x MXene/silver nanoparticles fiber membranes show good stability and little change in terahertz shielding effect after high temperature annealing. This may provide potential ideas about the development of high-performance terahertz shielding materials, which are of great significance of terahertz electromagnetic shielding.

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Recent Advances of Efficient Design of Terahertz Quantum-Cascade Lasers

Cited by 9 publications

References 44 publications

Extraction‐Dominated Temperature Degradation of Population Inversion in Terahertz Quantum Cascade Lasers

Extraction‐Dominated Temperature Degradation of Population Inversion in Terahertz Quantum Cascade Lasers

Studying the Synchronization for Multiple Transmitter- Receiver Nano Quantum Cascade Lasers.

Enhanced terahertz shielding by adding rare Ag nanoparticles to Ti₃C₂T _x MXene fiber membranes

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Recent Advances of Efficient Design of Terahertz Quantum-Cascade Lasers

Cited by 9 publications

References 44 publications

Extraction‐Dominated Temperature Degradation of Population Inversion in Terahertz Quantum Cascade Lasers

Extraction‐Dominated Temperature Degradation of Population Inversion in Terahertz Quantum Cascade Lasers

Studying the Synchronization for Multiple Transmitter- Receiver Nano Quantum Cascade Lasers.

Enhanced terahertz shielding by adding rare Ag nanoparticles to Ti3C2T x MXene fiber membranes

Contact Info

Product

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Enhanced terahertz shielding by adding rare Ag nanoparticles to Ti₃C₂T _x MXene fiber membranes