A new method for regulating optical properties of a coaxial cylindrical quantum well using the electric field and intense laser field is investigated in the effective mass approximation. By means of the finite difference method and the correct dressing effect of the confinement potential, the results show that the enhancement and recovery of optical absorption and refractive index change strongly depend on the multifaceted-cooperative regulation of the laser parameter, the electric field strength, the angle between the electric field and polarization direction of laser, and the barrier width. This is promising for the design of a new generation of highly polarization sensitive devices, optical repair equipments and optical phase modulators by adopting the multistage combination of electric and intense laser fields.
A new method for regulating optical properties of a coaxial cylindrical quantum well using the electric field and intense laser field is investigated in the effective mass approximation. By means of the finite difference method and the correct dressing effect of the confinement potential, the results show that the enhancement and recovery of optical absorption and refractive index change strongly depend on the multifaceted-cooperative regulation of the laser parameter, the electric field strength, the angle between the electric field and polarization direction of laser, and the barrier width. This is promising for the design of a new generation of highly polarization sensitive devices, optical repair equipments and optical phase modulators by adopting the multistage combination of electric and intense laser fields.
The coupling of intense laser field and electric field serves as a new method to achieve the desired electronic states, optical absorption coefficients and refractive index changes of cubic quantum dot for the first time, to the best of our knowledge. The stationary Schrödinger equation was derived and calculated by means of the Kramers-Henneberger transformation, the non-perturbative Floquet method, and the finite difference method. The energy-level anticrossing is activated by multi-physical field to transform suitable quantum states, resulting in the multiple-polarization-selective absorption and refractive index changes. The results show that ultra-wideband frequency shift and resonance enhancement characteristics of optical absorption coefficients and refractive index changes strongly depend on the laser-dressed parameter, the amplitude of electric field, and the polarization directions of the intense laser field and electric field.
External fields modify the confinement potential and electronic structure in a multiple quantum well system, affecting the light–matter interaction. Here, we present a theoretical study of the modulation of the nonlinear optical response simultaneously employing an intense non-resonant laser field and an electric field. Considering four occupied subbands, we focus on a GaAs/AlGaAs symmetric multiple quantum well system with five wells and six barriers. By solving the Schrödinger equation through the finite element method under the effective mass approximation, we determine the electronic structure and the nonlinear optical response using the density matrix formalism. The laser field dresses the confinement potential while the electric field breaks the inversion symmetry. The combined effect of both fields modifies the intersubband transition energies and the overlap of the wave functions. The results obtained demonstrate an active tunability of the nonlinear optical response, opening up the possibility of designing optoelectronic devices with tunable optical properties.
Abstractauthoren This paper investigates the effects of an intense laser field and electric field on the optical properties of quantum well represented by Morse potential. The non-resonant, high-frequency intense laser effects upon the system are treated within the framework of non-perturbative approach, modifying the confinement potential associated to the heterostructure. The analytical expressions of the linear and third-order nonlinear optical absorption coefficients and refractive index changes are obtained by using the compact-density matrix formalism. The results for a typical GaAs quantum well correspond to several configurations of the structural parameter, the strengths of the intense laser radiation, and the static electric field. Numerical results reveal the striking influence of the external fields on the magnitude and resonant peak energy positions of the optical absorption coefficients and refractive index changes. Besides, the control of intersubband optical transitions by the structure parameter seems feasible.
Abstract In this present study, the effects of electric, magnetic, and non-resonant intense laser field (ILF) on the linear, third-order nonlinear, and total optical absorption coefficients (TOACs) and relative refractive index changes (RRICs) of GaAs quantum well, having Hulthen confinement potential, were theoretically investigated. In addition, the dependence of the nonlinear optical properties in the structure on the optical intensity of incident photon and the inverse relaxation time was also calculated. To do this research, firstly the energy eigenvalues and eigenfunctions of the structure were calculated by using the effective mass and envelope function approaches. By using these calculated subband energy levels and wave functions belonging to these levels, the nonlinear optical properties of the system were obtained via the iterative method, within the compact density matrix approach framework. The obtained numerical results show that the optical properties of the considered system depend on the externally applied fields. With the applied external electric and magnetic field, the peak positions of TOACs and RRICs shift to higher energies, and the peak magnitudes increase. The high-frequency ILF applied to the structure shifts the peak positions of TOACs and RRICs initially towards higher energies and then towards lower energies and their peak sizes increase. These results show that the optical properties of the system can be adjusted purposively by changing the magnitude of applied external fields.
In this present study, we have theoretically investigated the effect of applied external electric field and non-resonant intense laser field, as well as the adjustable physical parameters (A, M, and η) of the system, on the linear and nonlinear of GaAs/GaAlAs cylindrical quantum dot. The confinement potential of the quantum dot is composed of the axial potential with a Razavy-type quantum well in the z-direction, and the cylindrical-type potential in the radial direction. To achieve this goal, the wave functions, and the corresponding eigenvalues of the electron are investigated by resolving the time-independent Schrödinger equation using the diagonalisation technique in terms of the effective mass approximation. The linear and nonlinear optical properties’ expressions have been calculated with the help of the compact density matrix method. Our numerical results show that by changing the A, M, and η parameters, we can see a blueshift or redshift in the total optical absorption coefficients (TOACs) and relative refractive index changes (RRICs). Additionally, they are redshifted, and their extrema increase as the radius increases. The increase in electric field or laser field intensities generates a strong displacement of the resonant peak position towards the higher energies, diminishes the TOACs magnitude, and shrinks RRICs extrema. The model potential used in the computation is important, and the study of it will be practical in the development and research of nanostructures systems.
Abstract We present a theoretical study on the effects of intense laser field (ILF) and static electric field on the linear and nonlinear optical properties of a cylindrical quantum dot with Rosen–Morse axial potential under the framework of effective mass and parabolic band approximations. This study also takes into account the effects of the structure parameters ( η , V 1 , and R ). The analytical expressions of the linear, third-order nonlinear and total optical absorption coefficients (TOACs) and the relative refractive index changes (RRICs) are obtained by using the compact-density-matrix approach. The results of numerical calculations show that the resonant peak position of the TOACs and RRICs shifts towards lower energies and the magnitude of the peak increases with the effect of the static electric field and ILF. In addition, it is observed that while the resonant energies of the TOACs and RRICs of system shift towards the higher (lower) energies with the enhancement of η , V 1 , they decrease with the augmentation of R . Thus, the findings of this study show that the optical properties of the structure can be adjusted by changing the magnitude of structure parameters and applied external fields.