Third-harmonic Generation Coefficient Research Articles

Research on third-harmonic generation with position-dependent mass in a quantum well: comment

We have discovered errors in the recent paper J. Opt. Soc. Am. B35, 1408 (2018)JOBPDE0740-322410.1364/JOSAB.35.001408. Specifically, we demonstrate that both the electric dipole matrix elements and the third-harmonic generation coefficient presented in the paper have mistakes. We also present the correct results for the electric dipole matrix elements and the third-harmonic generation coefficient.

Third-harmonic generation of a laser-driven quantum dot with impurity

The third-harmonic generation (THG) coefficient for a laser-driven quantum dot with an on-center Gaussian impurity under static magnetic field is theoretically investigated. Laser field effect is treated within the high-frequency Floquet approach and the analytical expression of the THG coefficient is deduced from the compact density-matrix approach. The numerical results demonstrate that the application of intense laser field causes substantial changes on the behavior of THG. In addition the position and magnitude of the resonant peak of THG coefficient is significantly affected by the magnetic field, quantum dot size and the characteristic parameters of the impurity potential.

Intense laser field effects on the third-harmonic generation in a quantum pseudodot system

In this research, we present the effects of high-frequency intense laser field on the third-harmonic generation associated with intersubband transitions in a two-dimensional quantum pseudodot system subjected to an uniform external magnetic field. Non-resonant monochromatic laser radiation with circular polarization is considered within the framework of high-frequency Floquet approach. On the basis of the compact-density matrix approach and an iterative method, the third-harmonic generation coefficient is calculated. The results presented for a GaAs quantum dot show that: (i) the position and magnitude of the resonant peak of third-harmonic generation depend strongly on magnetic field, the chemical potential and zero-point of pseudoharmonic potential; (ii) the strength of intense laser field modifies the confinement potential which results in considerable changes in the nonlinear optical response of the system.

Third-harmonic generation in a double ring-shaped quantum dot under electron-phonon interaction

In this work, the effect of electron-phonon (e-p) interaction on third-harmonic generation (THG) in a GaAs double ring-shaped quantum dot is studied. To this end, we have analytically obtained the energy levels and wave functions without the interaction between electron and phonon. Then, we have used THG coefficient which is obtained by using compact-density-matrix approach and iterative method. Numerical obtained results reveal that the THG coefficient is obviously increased and the peak positions shift toward higher energies after considering the e-p interaction.

Effect of position-dependent effective mass on nonlinear optical properties in a quantum well

In this study, the effect of position-dependent effective mass (PDM) on the nonlinear optical properties in a GaAs/AlAs semiconductor quantum well (QW) are intensively studied. Calculations are performed using both the position-dependent effective mass and a constant effective mass within the framework of the compact-density-matrix approach, iterative method, and coordinate transformation method. We have calculated the third-harmonic generation (THG) coefficients, the optical absorption (OA) coefficients and the refractive index changes (RIC) as a function of the incident photon frequency and obtained the energy eigenvalues and eigenfunctions of the system through solving the Schrödinger equation. The results show that spatially varying electron effective mass has a significant impact on the nonlinear optical properties in a quantum well.

Effect of electron–phonon interaction on the third-harmonic generation in a quantum pseudodot

In the present work, we numerically study the influence of electron–phonon (e–p) interaction on third-harmonic generation in a GaAs quantum pseudodot. For this goal, we have analytically obtained the energy levels and wave functions without the interaction between electron and phonon. Then, we have applied the third-harmonic generation coefficient which is obtained by using compact-density-matrix approach and iterative method. According to the obtained results, it is found that the third-harmonic generation coefficient is obviously enhanced and the peak positions shift toward higher energies after considering the e–p interaction.

Tuning third harmonic generation of impurity doped quantum dots in the presence of Gaussian white noise

We perform a broad exploration of profiles of third harmonic generation (THG) susceptibility of impurity doped quantum dots (QDs) in the presence and absence of noise. We have invoked Gaussian white noise in the present study. A Gaussian impurity has been introduced into the QD. Noise has been applied to the system additively and multiplicatively. A perpendicular magnetic field emerges out as a confinement source and a static external electric field has been applied. The THG profiles have been pursued as a function of incident photon energy when several important parameters such as electric field strength, magnetic field strength, confinement energy, dopant location, Al concentration, dopant potential, relaxation time and noise strength assume different values. Moreover, the role of the pathway through which noise is applied (additive/multiplicative) on the THG profiles has also been deciphered. The THG profiles are found to be decorated with interesting observations such as shift of THG peak position and maximization/minimization of THG peak intensity. Presence of noise alters the characteristics of THG profiles and sometimes enhances the THG peak intensity. Furthermore, the mode of application of noise (additive/multiplicative) also regulates the THG profiles in a few occasions in contrasting manners. The observations highlight the possible scope of tuning the THG coefficient of doped QD systems in the presence of noise and bears tremendous technological importance.

Nonlinear optical properties in square tangent quantum wells

The nonlinear optical properties in square tangent quantum wells are studied theoretically. We obtain eigenfunctions and energy eigenvalues by means of solving Schrödinger equation within the framework of effective mass approximation. Using the compact-density-matrix approach and iterative method, the analytic expressions of the third-harmonic generation (THG) coefficients, the optical absorption (OA) coefficients and the refractive index changes (RIC) are obtained. The results show that the THG coefficients are affected by d and U0, while the OA coefficients and the RIC are strongly affected not only by d and U0 but also by the incident optical intensity.

Effect of hydrogenic impurity on the third-harmonic generation in a quantum well

The third-harmonic generation (THG) coefficients in a quantum well with hydrogenic impurity are theoretically investigated with the compact-density-matrix approach and iterative method. The wave functions and the energy levels can be obtained by using variational method and numerical method. Numerical results show that the THG coefficients are strongly affected by the hydrogenic impurity.

A theoretical study of third-harmonic generation in semi-parabolic plus semi-inverse squared quantum wells

A theoretical study of third-harmonic generation is performed by using the compact-density-matrix method. An electron is confined in semi-parabolic potential plus semi-inverse squared potential quantum wells. Our calculations show that the absolute value, the imaginary part and the real part of third-harmonic generation coefficients are greatly influenced by the parabolic confinement frequency and the characteristic parameter of the inverse squared potential. The relationship between the absolute value and the imaginary part as well as the relationship between the absolute value and the real part is discussed. It is found that the resonant peaks of the absolute value originate from the imaginary part and are not related to the real part.

Studies on the third-harmonic generation coefficients in asymmetrical semi-exponential quantum wells

Third-harmonic generation (THG) coefficients in asymmetrical semi-exponential quantum wells (ASEQW) are studied theoretically. We obtain the eigenfunctions and the energy eigenvalues by means of solving Schrödinger equation within the framework of effective mass approximation. Besides, the analytic expression of THG coefficients is acquired through using compact-density-matrix approach and iterative method. The results show that both the amount of peaks of THG coefficients and the magnitude of peaks are significantly affected by σ and U0, which are parameters refer to the intensity of confinement potential in the growth direction of ASEQW.

Third-Harmonic Generation in Special Parabolic Quantum Wells

Third-harmonic generation in a special asymmetric quantum well is investigated. The third-harmonic generation coefficient is carried out by applying compact-density-matrix method. The numerical results are presented for a GaAs/AlGaAs asymmetric quantum well. The very large third-harmonic generation coefficient is obtained in this quantum well. Moreover, the third-harmonic generation coefficient dependents on the quantum well parameters are investigated, respectively.

Third harmonic generation in intraband transitions of spherical silicon quantum dots

A theoretical study of the third harmonic generation (THG) is reported involving intraband transitions in the conduction band of spherical Si semiconductor quantum dot surrounded by SiO2, Si3N4, and SiC matrix. The wave function and energies of a singly charged Si dot are calculated using the effective mass approximation. A finite barrier height is considered at the interface of the dot and the surrounding matrix. The results show that the THG coefficient of the silicon quantum dot strongly depends on the radius of the dot and the surrounding matrix.

The electric field effects on the third-harmonic generation in spherical quantum dots with parabolic confinement

The influence of an external electric field on the binding energies of the ground state and excited states with the third-harmonic-generation (THG) coefficient for spherical quantum dot (QD) with parabolic confinement is investigated theoretically. The energy levels and wave functions of electronic states in the QDs are calculated using by variational method within the effective-mass approximation. The numerical results demonstrate that the THG coefficient very sensitively depends on the magnitude of the electric field and the radius of the QDs. In addition, the THG coefficient also depends on the relaxation rate of the spherical QD with parabolic confinement and the position of impurity.

Third-harmonic generation in two-dimensional pseudo-dot system with an applied magnetic field

Third-harmonic generation (THG) in a two-dimensional quantum pseudo-dot system with an applied magnetic field is theoretically investigated. THG coefficient is obtained by using the compact-density matrix approach and an iterative method. Numerical results are presented for typical GaAs/AlGaAs pseudo-parabolic quantum dots. The results show that the external magnetic field and the geometrical size of the pseudo-dot system have evidently influences on the THG, whereas their influences are different.

Polaron effects on the third-harmonic generations in cylindrical quantum dots

The effect of the electron–LO-phonon interaction on the third-harmonic generation (THG) coefficient for cylinder quantum dots with an applied electric field is theoretically investigated, the THG coefficient is obtained by using compact-density-matrix approach and iterative method, and the numerical results are presented for a GaAs cylinder quantum dots. The results show that the THG coefficient is greatly enhanced and the peak shift to the aspect of high energy when considering the influence of electron–LO-phonon interaction.

Third-harmonic generation in cylindrical quantum dots in a static magnetic field

The third-harmonic generation (THG) coefficient for cylindrical quantum dots in a static magnetic field is investigated theoretically. By using the compact density-matrix approach and the iterative method, we obtain an analytical expression for the THG coefficient, and numerical calculations for typical GaAs/AlAs cylindrical quantum dots are presented. The results show that the THG coefficient can reach a magnitude of 10 −10 m 2/V 2. In addition to the radius R of the cylindrical quantum dots, both the parabolic confining potential and the static magnetic field have an influence on the THG coefficient.

Studies on the third-harmonic generations in cylindrical quantum dots with an applied electric field

The third-harmonic generation (THG) coefficient for cylinder quantum dots with an applied electric field is theoretically investigated. Using the compact density-matrix approach and the iterative method, we get the analytical expression of the THG coefficient, and the numerical calculations of the typical GaAs/AlAs cylinder quantum dots are presented. The results show that the THG coefficient can reach the magnitude of 10 −9 m 2/V 2. Apart from the length L and radius R of cylindrical quantum dots, both the parabolic confining potential and an applied electric field can also influence the THG coefficient.

GIANT THIRD-ORDER NONLINEARITIES IN ANHARMONIC QUANTUM WELLS

Third-harmonic generation (THG) and its origin are investigated in an anharmonic quantum well by the perturbation theory. The calculated results show that the nonlinear effect roots in an anharmonic oscillation of electrons deviate asymmetrically or symmetrically from an ideal harmonic oscillation, and the more the deviation is, the larger the nonlinearities will be. In addition, the nonlinear coefficient is also relative to the anharmonic-oscillation frequency in the model. The most important point is that the THG coefficient may be obtained over 10-10 (m/V)2, about ten orders of magnitude greater than those in bulk GaAs.

THIRD-HARMONIC GENERATION OF WURTZITEGaN-BASED COUPLING QUANTUM WELLS WITH STRONG BUILT-IN ELECTRIC FIELDS

Based on the density matrix approach and iterative treatment, the third-harmonic generation (THG) susceptibility of a wurtzite nitride coupling quantum well (CQW) with strong built-in electric fields have been theoretically investigated. The band non-parabolicity effect of nitride heterostructures has been taken into account. A typical wurtzite AlGaN/GaN CQW are chosen to perform numerical calculations. The result shows that, the THG coefficients sensitively depend on the structural parameters of the CQW system. Moreover, a strong THG process can be realized in the nitride CQW by choosing a group of appropriate structural parameters and doped fraction.