Effects of design parameters on the performance of terahertz quantum-cascade lasers

Li, He Ping; Cao, Juncheng; Liu, H C

doi:10.1088/0268-1242/23/12/125040

Cited by 16 publications

(15 citation statements)

References 27 publications

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“…(22) can in principle only be determined by detailed carrier transport simulations, simpler and much faster approaches are often adopted, e.g., for design optimizations of experimental QCL structures over an extended parameter range. Frequently, Fermi-Dirac statistics is applied, 57,66 with…”

Section: E Schrödinger-poisson Equation Systemmentioning

confidence: 99%

Modeling techniques for quantum cascade lasers

Jirauschek

Kubis

2014

Applied Physics Reviews

227

178

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Quantum cascade lasers are unipolar semiconductor lasers covering a wide range of the infrared and terahertz spectrum. Lasing action is achieved by using optical intersubband transitions between quantized states in specifically designed multiple-quantum-well heterostructures. A systematic improvement of quantum cascade lasers with respect to operating temperature, efficiency and spectral range requires detailed modeling of the underlying physical processes in these structures. Moreover, the quantum cascade laser constitutes a versatile model device for the development and improvement of simulation techniques in nano- and optoelectronics. This review provides a comprehensive survey and discussion of the modeling techniques used for the simulation of quantum cascade lasers. The main focus is on the modeling of carrier transport in the nanostructured gain medium, while the simulation of the optical cavity is covered at a more basic level. Specifically, the transfer matrix and finite difference methods for solving the one-dimensional Schr\"odinger equation and Schr\"odinger-Poisson system are discussed, providing the quantized states in the multiple-quantum-well active region. The modeling of the optical cavity is covered with a focus on basic waveguide resonator structures. Furthermore, various carrier transport simulation methods are discussed, ranging from basic empirical approaches to advanced self-consistent techniques. The methods include empirical rate equation and related Maxwell-Bloch equation approaches, self-consistent rate equation and ensemble Monte Carlo methods, as well as quantum transport approaches, in particular the density matrix and non-equilibrium Green's function (NEGF) formalism. The derived scattering rates and self-energies are generally valid for n-type devices based on one-dimensional quantum confinement, such as quantum well structures

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Section: E Schrödinger-poisson Equation Systemmentioning

confidence: 99%

Modeling techniques for quantum cascade lasers

Jirauschek

Kubis

2014

Applied Physics Reviews

227

178

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“…As mentioned above, the frequency BA f in the characteristic admittance expressions for the capacitor and inductor in one Q-TLM unit is determined by the generated photon through intersubband electron transitions; it can be obtained by calculating the band structure of the cascade quantum wells. In the simulation, the band structure is varied with the bias current [40] and the sampling frequency sam f needs to satisfy the Nyquist-Shannon sampling theorem; The optical confinement factor and the spontaneous emission coefficient are chosen based on the empirical values. In the following, the proposed Q-TLM model is used to analyze the output properties of an exemplar / GaAs AlGaAs THz QCL in the time and frequency domains.…”

Section: Theoretical and Experimental Analysis Of Thz Quantum Camentioning

confidence: 99%

Quantum Transmission Line Modeling and Experimental Investigation of the Output Characteristics of a Terahertz Quantum Cascade Laser

Xia

Rubino

et al. 2020

IEEE Trans. THz Sci. Technol.

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We describe a new approach to modelling the optoelectronic properties of a terahertz-frequency quantum cascade laser (THz QCL) based on a quantum transmission line modelling (Q-TLM) method. Parallel quantum cascade transmission line modelling units are employed to describe the dynamic optical processes in a nine-well THz QCL in both the time and frequency domains. The model is used to simulate the current-power characteristics of a QCL device and good agreement is found with experimental measurements, including an accurate prediction of the threshold current and emitted power. It is also confirmed that the Q-TLM model can accurately predict the Stark-induced blue shift of the emission spectrum of the THz QCL with increasing injection current. Furthermore, we establish the new Q-TLM model to describe the properties of a THz QCL device incorporating a photonic lattice patterned on the laser ridge, by linking the transmission line structure to each scattering module. The predicted effects of the lattice structure on the steadystate emission spectra of the THz QCL, including the side-mode suppression, are found to be in good agreement with experimental results. Our Q-TLM modelling approach is a promising tool for the future design of THz QCLs and analysis of their temporal and spectral behaviors.

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“…Approximations (Cassan 2000;Li et al 2008e) based on Fermi-Dirac statistics are used to determine electron sheet density on subbands and such estimate value is used to solve Schrödinger-Poisson equations self-consistently only once prior to MC simulation (Manenti et al 2003;Bonno et al 2005;Li et al 2008e). Modified algorithm has been proposed (Borowik et al 2012) and it requires preliminary calculation of subbands populations by rate equation method.…”

Section: Space-charge Effectmentioning

confidence: 99%

Monte Carlo modeling applied to studies of quantum cascade lasers

2017

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One of the commonly used approaches of solving electron transport problems in quantum cascade lasers (QCL) is the Monte Carlo (MC) method, based on semiclassical description in the framework of the Boltzmann Transport Equation. A major benefit of MC modeling is that it only relies on well-established material parameters and structure specification, in most cases without the need to use phenomenological parameters. The results of the modeling can be easily interpreted and they give microscopic insight of QCL operation. The goal of the present paper is to review the application of the MC technique to the studies of operation of QCL. The description of the components of the simulation algorithm is provided. Various physical mechanisms governing electron transport in QCL are described and their influence on the operation are reviewed.

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Effects of design parameters on the performance of terahertz quantum-cascade lasers

Cited by 16 publications

References 27 publications

Modeling techniques for quantum cascade lasers

Modeling techniques for quantum cascade lasers

Quantum Transmission Line Modeling and Experimental Investigation of the Output Characteristics of a Terahertz Quantum Cascade Laser

Monte Carlo modeling applied to studies of quantum cascade lasers

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