Optical Rectification Coefficient Research Articles

Modulation of nonlinear optical rectification, second, and third harmonic generation coefficients in n-type quadruple δ-doped GaAs quantum wells under external fields

The paper theoretically explores the variations in nonlinear optical rectification (NOR), second (SHG), and third harmonic generation (THG) coefficients of an n-type quadruple δ-doped GaAs quantum well in the presence of electric, magnetic, and THz laser fields. The energies of subbands and associated wave functions are derived through the solution of the Schrödinger equation, utilizing effective mass and parabolic band approximations. The findings indicate that the applied external electric and magnetic fields significantly influence both the magnitudes and the positions of the peaks in NOR, SHG, and THG concerning the incident photon energies. In addition to the influences of electric and magnetic fields, subjecting the system to an intense laser field results in noticeable changes in the THG, SHG, and NOR coefficients. These numerical findings regarding the optical properties of quadruple δ-doped quantum wells in the presence of external fields could offer valuable guidance for experimental studies.

Nonlinear optical properties of tunable spherical quantum dots under like-screened Kratzer potential

Using the effective mass approximation and the iterative procedure, we study the optical rectification (OR) coefficient of a spherical quantum dot (QD) system with like-screened Kratzer potential (LSKP), taking into account the influence of the confinement potential depth, quantum size and external environment. Our results show that the magnitude of the OR coefficient is strongly dependent on the magnitude of the tunable factor, whose peak value will be red-shifted or blue-shifted. Interestingly, the limiting potential depth and temperature have opposite effects on the OR coefficient in terms of peak location and size. Therefore, it is necessary to pay more attention to the influence of internal and external parameters on nonlinear optical effects, and apply the theory to practical experiments and the manufacture of optoelectronic devices.

High harmonic generations triggered by the intense laser field in GaAs/AlxGa1-xAs honeycomb quantum well wires

Under constant electric and magnetic fields, the potential profile of the honeycomb quantum well wire (HQWW) is studied for varying intense laser fields to trigger and optimize high harmonics (nonlinear optical rectification, second and third harmonic generation coefficients). The finite element method has been used to simulate wavefunctions and their corresponding energy levels under effective mass approximation. We have shown that an intense laser field reshapes the potential profile of the HQWW, and this results in maximum and minimum for dipole moment matrix elements and energy differences. The increase and decrease of energy differences create blue and red shifts in the optical spectrum. In the end, we have calculated nonlinear optical rectification as 11.1x10−5 m/V. The second harmonic generation coefficient is found as 18.4x10−7 m/V which is three times and a lot bigger than bulk GaAs and GaAs/AlGaAs superlattice. The third harmonic generation coefficient is calculated as 6.2x10−15 m2/V2. As a conclusion, we have shown that HQWW can be used in harmonic generation-based optical devices.

Nonlinear optical rectification of GaAs/GaAlAs quantum dot under tangent square potential

We have investigated in detail the effects of the depth and range of the limiting potential, the quantum size parameter, temperature and hydrostatic pressure on the nonlinear optical rectification (NOR) coefficient in GaAs/GaAlAs parabolic quantum dots (QDs) with a tangent square potential. Firstly, we add the tangent-square potential of the system along the z-axis to the original parabolic QD, and then the corresponding Schrödinger equation of the modified system can be solved to find the analytical forms of different splitting energy levels and envelope wave functions. Finally, the analysis and conclusions of the numerical simulations indicate that the above parameters have significant effects on the nonlinear optical properties of the modified system.

Effects of external fields on the nonlinear optical rectification and second harmonic generation of GaAs/GaAlAs zigzag quantum well

For the first time, the impact of externally applied static electric and magnetic field on the nonlinear optical rectification (NOR) and second harmonic generation (SHG) coefficients of GaAs/GaAlAs zigzag quantum well is theoretically investigated in this study. Additionally, we examined the effect of physical parameters such as width and depth of the structure on these coefficients. We have numerically solved the time-independent Schrödinger equation by using the diagonalization method under the effective mass approximation for obtaining subband energy levels and wave functions of the structure, and then we have used the compact density matrix method to obtain the analytical expressions of NOR and SHG coefficients. The obtained numerical results showed that when the magnitude of the externally applied electric and magnetic fields is increased, the peak position of NOR and SHG shifts to blue, and by increasing the width and potential depth of the quantum well, it shifts to red.

Electric field effect on anisotropic nonlinear optical properties of GaN/AlN quantum dots with multitype-tunable shape

A new investigation on anisotropic nonlinear optical properties of GaN/AlN quantum dots with multitype-tunable shape under electric field have been performed in the effective mass approximation. By means of the finite difference method, the results show that continuously graded elliptic-like quantum dots have higher polarization stability on nonlinear coefficients. The enhancement and abort of the second-harmonic generation, the optical rectification and third-harmonic generation coefficients strongly depend on the asymmetry of quantum dots, the electric field strength and direction, and polarization direction of incident wave.

The nonlinear optical rectification, second and third harmonic generation coefficients of Konwent potential quantum wells

The nonlinear optical rectification, second and third harmonic generation coefficients of Konwent potential quantum wells

Effect of Razavy potential well parameters on the optical rectification, second, and third harmonic generation coefficients of Razavy quantum well in the presence of electric, magnetic, and THz laser fields

Effect of Razavy potential well parameters on the optical rectification, second, and third harmonic generation coefficients of Razavy quantum well in the presence of electric, magnetic, and THz laser fields

Investigation of the nonlinear optical rectification coefficient in a multilayered spherical quantum dot

In the framework of the effective mass approximation, we have investigated the effects of hydrostatic pressure, temperature, nonparabolicity of the band, and polaronic mass on nonlinear optical rectification. Furthermore, the optical rectification coefficient's dependency on the inner dot radius and the barrier width is also investigated. The obtained results reveal that geometrical sizes, hydrostatic pressure, and temperature all have a significant impact on the nonlinear optical rectification. Moreover, the combined effects of the conduction band nonparabolicity and polaronic mass produce a redshift of the peak position and a reduction in the resonant peak magnitude.

Nonlinear optical rectification of tuned quantum dots under the action of a vertical magnetic field

The changes of optical rectification (OR) coefficient in tuned quantum dots under the action of the external magnetic field, hydrostatic pressure, temperature and quantum dot radius are theoretically studied in detail. The tuned quantum dots are subjected to a uniform magnetic field perpendicular to the structural plane. Within the framework of effective mass approximation and parabolic band approximation, the energy level and wave function are derived, and the nonlinear OR coefficient is calculated by compact density matrix theory and iterative method. Numerical results show that the resonance peak of the OR coefficient moves in the direction of high energy or low energy under different constraint parameters, that is, red shift or blue shift. At the same time, the peak value of the OR coefficient will increase or decrease with the change of the parameters.

Spherical quantum dot in modified Kratzer–Coulomb potential: study of optical rectification coefficients

We consider the effects of quantum dot radius, confinement potential depth and controllable effective mass on the optical rectification coefficient (ORC) in spherical quantum dots, which is confined with Modified Kratzer–Coulomb Potential (MKCP). Using the Nikiforov–Uvarov method and compact density matrix theory, the ground state energy, ORC and wave function of electrons under the combined action of many factors are calculated. The results show that they affect the optical rectification response from different angles, including the position of peak and formant.

Nonlinear optical rectification of GaAs/AlηGa1−ηAs quantum dots system with Hulthén-Yukawa Potential

The impacts of structural parameters on the nonlinear optical rectification (NOR) coefficient in GaAs/AlηGa1−ηAs quantum dots (QDs) with Hulthén-Yukawa Potential (HYP) are explored in the reported work, including quantum dot radius, limiting potential depth, Al-concentration, hydrostatic pressure and temperature. The Nikiforov-Uvarov (N–U) method is used to solve the Schrödinger equation corresponding to the restricted quantum dot system, at the same time, the subband energy level and the propagation wave function are obtained, the numerical expression of the NOR coefficient is calculated by using compact density matrix theory and iterative method. Last but not least, the results of data analysis show that these factors have an obvious influence on the nonlinear optical characteristics of the model system, it includes the change of peak value and the redshift or blueshift of coefficient formant.

Nonlinear Optical Rectification in an Inversion-Symmetry-Broken Molecule near a Metallic Nanoparticle.

We study the nonlinear optical rectification of an inversion-symmetry-broken quantum system interacting with an optical field near a metallic nanoparticle, exemplified in a polar zinc–phthalocyanine molecule in proximity to a gold nanosphere. The corresponding nonlinear optical rectification coefficient under external strong field excitation is derived using the steady-state solution of the density matrix equations. We use ab initio electronic structure calculations for determining the necessary spectroscopic data of the molecule under study, as well as classical electromagnetic calculations for obtaining the influence of the metallic nanoparticle to the molecular spontaneous decay rates and to the external electric field applied to the molecule. The influence of the metallic nanoparticle to the optical rectification coefficient of the molecule is investigated by varying several parameters of the system, such as the intensity and polarization of the incident field, as well as the distance of the molecule from the nanoparticle, which indirectly affects the molecular pure dephasing rate. We find that the nonlinear optical rectification coefficient can be greatly enhanced for particular incident-field configurations and at optimal distances between the molecule and the metallic nanoparticle.

Intense laser field effect on the nonlinear optical properties of triple quantum wells consisting of parabolic and inverse-parabolic quantum wells

The nonlinear optical rectification, the second harmonic generation coefficient, and the third harmonic generation coefficient in parabolic-inverse parabolic-parabolic quantum wells (PIPPQWs) and inverse parabolic-parabolic-inverse parabolic quantum wells (IPPIPQWs) are calculated varying the intense laser field (ILF) parameter (). The modifications of the dipole moment matrix elements and the energy levels are depending on the potential shape. The results show that the ILF intensity exerts an active influence on the profile, height, and width of the confinement potential of both PIPPQW and IPPIPQW. The potential profile of IPPIPQW has been affected otherwise than PIPPQW for different ILF intensities. The nonlinear optical rectification, the second harmonic generation, and the third harmonic generation coefficients of PIPPQW and IPPIPQW could be altered in the energy range and the size of the resonance peak by rising the ILF intensity. By changing the parameter, it is conceivable to organize red or blue shift at the resonance peak positions of the nonlinear optical rectification, the second harmonic generation, and the third harmonic generation coefficients. The shift of the nonlinear optical rectification coefficient occurs when the difference between the ground and the second energy levels changes. According to the parameters used here, while for PIPPQW the spectrum of the resonance peak of the nonlinear optical rectification displays a blue shift with increasing ILF, this spectrum displays a red shift for IPPIPQW. The consequences can be valued in investigating new ways of changing the optical and electronic properties of semiconductor quantum wells.

Intensity-dependent nonlinear optical properties in an asymmetric Gaussian potential quantum well-modulated by external fields

In this paper, the effects of external electric, magnetic and non-resonant intense laser fields on the nonlinear optical rectification (NOR), second-harmonic (SH), and third harmonic (TH) generation in a GaAs quantum well with asymmetrical Gaussian potential are theoretically investigated. Firstly, the energy eigenvalues and eigenfunctions of a single electron confined in the structure are obtained by using the diagonalization method within the framework of the effective-mass and parabolic band approaches. Then, using these energy eigenvalues and eigenfunctions, expressions derived within the compact density matrix approximation have been employed to calculate the coefficients of the nonlinear optical response in the structure. The obtained simulation results show that the influence of the external fields leads to significant changes in the coefficients of nonlinear optical rectification, second and third harmonic generation in the system. As a result, it has been seen that the amplitude and position of the peaks of nonlinear optical rectification, second and third harmonic coefficients can be controlled by changing the applied external fields.

Optical rectification coefficient of GaAs/AlxGa1−xAs Thue–Morse multiple quantum wells

In the present work, we numerically investigate the optical properties of GaAs/AlxGa1−xAs Thue–Morse multiple-quantum-well systems (TM-MQWs) in the presence of an external electric field. We study the effects of the layers arrangements, total system length, number of layers and composition parameter x on the optical rectification coefficient of the TM-MQWs. We also consider three structural cases within which the system can be fabricated by repeating two, three or four composition parameters x1, x2, x3 and x4 in the adjacent layers. The most tunable ORC amplitude is due to the systems containing four different composition parameters and least tunable one is the systems which contain two different composition parameters. By increasing the number of layers, the ORC peak position periodically redshifts and blueshifts. We also show that by using the number of layers, total system length and composition parameter x, the ORC peak amplitudes are greatly tunable in a considerably large interval. This fact shows that the Thue–Morse MQWs are suitable candidates for optoelectronic device applications.

Retraction Note: Optical rectification and absorption coefficients studied by a short-range topless exponential potential well with inverse square root

This article has been retracted.

Nonlinear optical properties of n-type asymmetric double $$\delta $$-doped quantum wells: role of high-frequency laser radiation, doping concentration and well width

A numerical investigation on the nonlinear optical rectification, second and third harmonic generation coefficients in asymmetric double n-type $$\delta $$ -doped GaAs quantum well is performed in order to identify the influence of non-resonant intense laser radiation, doping concentration and the change in well widths. The energy eigenvalues and the corresponding eigenfunctions are determined by using effective-mass and parabolic band approximations. The working analytical expressions for the optical coefficients are derived from the iterative solving of compact-density matrix description of dielectric susceptibility. The obtained results reveal that the position and amplitude of the nonlinear optical rectification, second and third harmonic generation coefficients can be altered by modifying the external field as well as the compositional and geometrical setups.

Effects of interdiffusion and electric field on the optical rectification coefficient of GaAs/AlwGa1−wAs systems: crossover from single to multiple quantum wells

In the current study, we numerically investigate the optical properties of interdiffused GaAs/AlwGa1−wAs multiple quantum well systems under the influence of an external electric field. We solve the resulting Schrodinger equation by using a finite element method and present the algorithm. Here, our motivation was that the interdiffusion effect leads to a non-square more realistic confining potential profile. By using few animations, we show that the effect of the interdiffusion on the optical properties of the mentioned system is not so simple and trivial as has so far been described. These videos can also help experimentalists to select easier their physical parameters. The peak position and amplitude of optical rectification coefficient and probability density can be tuned using parameters such as interdiffusion length Ld, composition amplitude w0, electric field, system length and number of wells.

Optical properties of n-type asymmetric triple δ-doped quantum well under external fields

We present a theoretical investigation about the the influence of external electric, magnetic and non-resonant intense laser fields on intersubband-related second harmonics generation (SHG) and the nonlinear optical rectification (NOR) coefficients in n-type asymmetric triple δ-doped quantum wells (QWs). A particular design of asymmetric triple δ-doped QW with Lw = 200 Å width and, respectively, in the left side, central and right side, and doping concentrations is taken into account. For QWs under the combined effect of the external electric, magnetic and laser fields, the time-dependent wave equation is modified by using Kramers-Henneberger transformation and the dipole approximation. The subband energy spectra and the electronic wave functions are obtained by solving numerically the wave equation. The originality of this work can be presented as; (i) The results explain NOR and SHG characteristics of triple QW depending on external field effects in detail. The effects of the electric, magnetic and laser field on transition energies and NOR, SHG characteristics are presented detail. (ii) In addition to, the alternativeness to each other of the external fields is discussed by probing the features of SHG and NOR under the strong and weak regimes of external fields. (iii) These nonlinear optical responses to the external fields are compared, researching the optimum cases for these optical specifications. (iv) The control of SHG through the external fields in triple δ-doped QWs reveals to be easier and more precise.