Effect Of Laser Field Research Articles

Effects of magnetic, electric, and non-resonant intense laser fields on exciton binding energy and exciton absorption in a symmetric Gaussian single quantum well

Effects of magnetic, electric, and non-resonant intense laser fields on exciton binding energy and exciton absorption in a symmetric Gaussian single quantum well

Coupled cylindrical quantum well wires in broken symmetry: effects of intense laser field on the harmonic generations

Coupled cylindrical quantum well wires in broken symmetry: effects of intense laser field on the harmonic generations

Laser field effect on binding energy and self-polarization of an impurity in a double square quantum well made of three different materials

Laser field effect on binding energy and self-polarization of an impurity in a double square quantum well made of three different materials

Ripple and Lotus Phenomenon: Radiation Pattern Evolution of Nonlinear Thomson Scattering Under Cooperative and Competitive Effects of Applied Magnetic and Laser Field

Ripple and Lotus Phenomenon: Radiation Pattern Evolution of Nonlinear Thomson Scattering Under Cooperative and Competitive Effects of Applied Magnetic and Laser Field

Effects of non-resonant intense laser, electric and magnetic fields on exciton binding energy and absorption spectra in the Gaussian double quantum well

Effects of non-resonant intense laser, electric and magnetic fields on exciton binding energy and absorption spectra in the Gaussian double quantum well

Non-resonant intense laser field and electric field effects on the optical characterization of Rosen-Morse quantum wells with different potential functions

Non-resonant intense laser field and electric field effects on the optical characterization of Rosen-Morse quantum wells with different potential functions

Second harmonic generation in Harmonic-Gaussian asymmetric double quantum well: effect of magnetic and intense laser fields

We have theoretically analyzed the effects of externally applied fields (magnetic and intense laser) as well as various structural parameters such as well width, barrier width, barrier height, and structural asymmetry on the second harmonic generation (SHG) coefficients of GaAs/Al0.3Ga0.7As Harmonic-Gaussian asymmetric double quantum wells (QW). The time-independent Schrödinger equation was solved using the diagonalization method and effective mass approximation to obtain the energy eigenvalues and eigenfunctions of the structure. An expression derived within the compact density matrix approach has been used to evaluate the second harmonic generation (SHG) coefficient. Our numerical results indicate that increasing the magnitude of the magnetic (intense laser) field causes the peak positions of SHG to shift towards higher energy regions/blue (lower energy regions/red). On the other hand, as the structural parameters A1 and A2 ( k and z0 ) increase, the peak positions of the SHG coefficients exhibit a shift towards higher energy regions/blue (lower energy regions/red). We expect that the results of our study will contribute to the development of new optoelectronic devices based on the Harmonic-Gaussian asymmetric double quantum well structure.

Radiative dynamics of laser-driven Li@C n embedded in quantum plasma

This work considers a guest Lithium atom (Li@C n ) in an endohedral fullerene, embedded in a quantum plasma modeled by the more general exponential cosine screened Coulomb (MGECSC) potential, under the influence of a spherical confinement and laser radiation field. The system is examined in nonrelativistic form and the related wave equation is solved using the tridiagonal matrix method (TMM), thus obtaining the discrete-continuum spectrum and related wave functions. The numerical values of the relevant parameters in this process are physically accessible values. The effects of the plasma, laser field and endohedral cavity on the photoionization cross section (PCS) are analysed in detail. The shielding effect of the plasma medium and the pulsating effect of the laser field modify the effective potential energy of the system, affecting the localizations of the 2s and continuum states, causing various overlapping cases. Considering different values of the endohedral encompassement parameters, which means that different types of fullerenes are taken into account, overlapping cases occur for different spectra and wave functions. Scrutinising these overlappings, the confinement and Cooper resonances of the PCSs are analysed. This analysis provides many details for the radiative dynamics of an artificial system Li@C n . The relevant ranges and critical values of plasma, laser field, and endohedral encapsulation parameters in the formation process of these resonances and PCSs are explained, as well as the cross-section curves, resonance positions, effective photoelectron energy range, and general PCS behavior, which can be important for potential experiments in addition to other theoretical investigations.

Controlling the interband transitions in a triple quantum ring: Effects of intense laser and electric fields

In this paper, we theoretically studied the interband transitions in a three-dimensional structure of GaAs/Al0.3Ga0.7As triple concentric quantum rings approximating a reported experimental case. An intense non-resonant laser field and/or a static electric field were appropriately chosen to investigate the heavy-hole spectra and the interband transitions. For the combined actions of the two fields acting in the horizontal plane of the structure, we considered parallel and perpendicular directions. In each study, the effects on the heavy-hole energy spectra were discussed concerning their relationship with wave function localization. The radiative recombination energies, overlap integrals, and interband transition lifetime emphasize regions of interest for efficient control of the radiative decay, which is important for practical applications.

Influence of strong laser field on nuclear <i>α</i> decay

With the development of pulse amplification and compression technology, the peak power of the pulse has been improved by several orders of magnitude, and it is possible for the ultra strong laser field to affect nuclei directly. The <i>α</i> decay, as one of the most major forms in nuclear reaction, is a critical research topic in nuclear physics. According to the theory of Gamow model explaining nuclear <i>α</i> decay in quantum mechanics, double folding model solving nuclear potential energy, and cluster model describing atomic nucleus, we present a complete set of solutions for the half-life of nuclear <i>α</i> decay to study the influence of ultra strong laser field on nuclear <i>α</i> decay. These half-lives of <i>α</i> decay of different nuclei from medium to heavy in the absence of laser field are obtained, which accord well with the experimental data. Subsequently, we introduce the effects of ultra strong laser field into our theoretical method to achieve the variations of the half-life of nuclear <i>α</i> decay. Considering that the optical period of the laser pulse is much longer than the theoretical tunneling time and the Lorentz force is much smaller than the Coulomb force, the laser field is treated as an electrostatic field. The results show that the half-life of nuclear <i>α</i> decay will reduce about 0.1% by the strong laser field with a peak power density of about 1.0×10<sup>26</sup> W/cm<sup>2</sup>, demonstrating that the half-life of nuclear <i>α</i> decay is effectively affected by the strong laser field. Furthermore, the influences of the nuclear parameters, e.g. total quantum number <i>G</i> describing <i>α</i> particle orbits, and <i>α</i> decay reaction energy <i>Q</i><sub><i>α</i></sub>, on the variations of these half-lives of <i>α</i> decay of different nuclei are discussed with the help of the calculation results. The dependence of the half-lives of nuclear <i>α</i> decay on the laser peak power density is also explained correspondingly. In summary, we provide a more accurate method of calculating the half-life of nuclear <i>α</i> decay, which is used to study the influences of ultra strong laser field on these half-lives of nuclear <i>α</i> decay of different nuclei. With the further construction of strong laser devices, more interesting phenomena and results will be found from the experiment on the atomic nucleus under strong laser field.

Finite element 3D model of a double quantum ring: effects of electric and laser fields on the interband transition

In this work, the changes in the energy of electrons and holes, oscillator strength and interband transition time when external fields are applied to a GaAs/AlGaAs semiconductor double ring grown by the droplet epitaxy technique are theoretically analyzed. We consider a static electric field and an intense laser field nonresonant with the quantum structure, with variable intensities and orientations with respect to the symmetry axis of the quantum ring (QR). In the formalism of the effective mass approximation for electrons and holes, the energies and wavefunctions were numerically computed using the finite element method implemented with an accurate three-dimensional model of the real QR. Laser dressing of the confining potential was performed using the exact integration formula at each point. Our results show major differences between the effects of the two types of applied fields, caused mainly by the static electric-field-induced strong polarizability of the confined electron-hole pair. In addition, the effects of both fields exhibit strong anisotropy in the electronic properties as a result of the particular flattened geometry of the QR. Proper combinations of field strengths and orientations are helpful in designing accurate tools for the sensitive manipulation of interband radiative properties.

Combined Effects of Intense THz Laser Field and Applied Electric Field on Binding Energy of Exciton in GaAs/GaAlAs Finite Spherical Quantum Dot

This paper describes the combined effects of intense THz laser field and electric field on the ground state binding energy of heavy hole excitons confined in GaAs/ GaAlAs spherical finite quantum dots. The formulation is based on the model of “laser dressed potential” which combines Coulomb interaction and field effect in only one potential as reported in the literature. The calculation is performed by using the variational method in the framework of the single band effective mass theory. Our results show that (i) the laser field increases the electron and hole confinement energy that form the exciton in the QD until they reach a maximum, then they become almost constant for an intense laser field, (ii)the electric field and the laser field lowers the binding energy for all quantum dot radii making the exciton stabilized and clustered near the center of the dot, and iii)the laser field increases the spatial extension of exciton but the electric field decreases it linearly.

Laser field effect on the normalized self-polarization, self-polarization and binding energy in square quantum wells made of different materials

In this study, we examine the effect of the laser field on normalized self-polarization, self-polarization, and binding energy in square quantum wells made of four different materials under effective mass approximation. The effects of well width, laser field, and impurity position on normalized self-polarization, self-polarization, and binding energies are shown in detail. The subband energies are obtained by the finite difference method, and the impurity energies are calculated by the variational method. The laser field significantly affects binding energy, self-polarization, and normalized self-polarization. The term normalized self-polarization is defined for the first time in this study. This allows a more detailed examination of the self-polarization change depending on the impurity position. Examining the laser field effect, especially in square quantum wells made of different materials, will provide researchers with helpful information about the importance of material selection in calculating binding energy, self-polarization, and normalized self-polarization.

Intense Laser Field Effect on the Photo-Ionization Cross-Section of the First Exciton Transition in a Core/Shell Quantum Dot Submitted to an Applied Electric Field

In the current work, we study the intense laser pulse influences on the behaviors of the first excitonic transition in a core/shell quantum dot submitted to an electric field. Therefore, the exciton binding energy and the mean distance between the correlated electron–hole pair are discussed, considering the electric field and laser strength. Our calculations show that both external fields play significant repulsive effects. Through their effects, they oppose the attractive nature of the Coulomb potential between the correlated pair, which decreases the excitonic binding energy. We also analyze the dissociation process by determining the photo-ionization cross-section (PICS). Our findings show that the peaks of the PICS redshift when the shell thickness b−a increases. For a given core radius, the laser and electric field induce a shift toward the low-energy region for the PICS; this displacement is more pronounced for the laser case. Our study also compares simple quantum dots and core/shell quantum dots to show the effect of the inner radius on the obtained results. Our theoretical results can lead to promising applications of exciton-based devices controlled by sizes and external fields.

Optical Gain of a Spherical InAs Quantum Dot under the Effects of the Intense Laser and Magnetic Fields

In quantum dots, where confinement is strong, interactions between charge carriers play an essential role in the performance of semiconductor materials for optical gain. Therefore, understanding this phenomenon is critical for achieving new devices with enhanced features. In this context, the current study examines the optical properties of an exciton confined in a spherical InAs quantum dot under the influence of magnetic and intense laser fields. We investigate the oscillator strength, exciton lifetime, and optical gain, considering the effects of both external fields. We also pay particular attention to the influence of quantum dot size on the results. Our calculations show that the two external fields have opposite effects on our findings. Specifically, the applied magnetic field increases the oscillator strength while the intense laser reduces it. In addition, the optical gain peaks are redshifted under the application of the intense laser, whereas the magnetic field causes a blueshift of the peak threshold. We also find that both external perturbations significantly influence the exciton lifetime. Our study considers the outcomes of both the exciton’s ground (1s) and first excited (1p) states. The theoretical results obtained in this study have promising implications for optoelectronic devices in the ∼3–4 μm wavelength range only through the control of quantum dot sizes and external perturbations.

Nonlinear absorption coefficient and relative refractive index change for Konwent potential quantum well as a function of intense laser field effect

Nonlinear absorption coefficient and relative refractive index change for Konwent potential quantum well as a function of intense laser field effect

Combined effects of intense THz laser field and applied electric field on binding energy of exciton in GaAs/ GaAlAs finite spherical quantum dot

Combined effects of intense THz laser field and applied electric field on binding energy of exciton in GaAs/ GaAlAs finite spherical quantum dot

Proton emission from halo nuclei induced by intense x-ray lasers

We investigate the proton emission from halo nuclei induced by intense x-ray lasers within the framework of a nonperturbative quantum $S$-matrix approach. We have analytically deduced the angular differential as well as the total multiphoton rates of the proton emissions. For a linearly polarized x-ray laser field, we find that the angular distributions of proton emission sensitively depend on the laser frequency and show an interesting petal structure with increasing laser frequency as well as the number of absorbed photons. Meanwhile, we find the Coulomb repulsion potential between the proton and the remainder nucleus has a strong hindering effect on the total multiphoton rates of the proton emissions and leads to the blueshifts of the multiphoton transition frequency. Moreover, the polarization effects of laser fields on total rates of proton emission have also been addressed. We find that the polarized ellipticity corresponding to the maximum of the total rates depends on the laser frequency showing a transition from perturbative to nonperturbative proton emission. The underlying mechanism of the above findings is uncovered, and some implications are discussed.

Theoretical investigation of laser field effect on nonlinear optical properties of quantum dots

In this work, we have theoretically investigated the effects of a high-frequency intense laser field on the nonlinear optical properties of a two-dimensional Gaussian quantum dot system. A non-resonant monochromatic intense laser field with circular polarization applied to the system is considered in the framework of a non-perturbative approach. The nonlinear optical properties of the system have been investigated by using the compact-density matrix approach and iterative procedure. The laser field effect on the linear and the third-order nonlinear absorption coefficients and refractive index changes have been examined. Results reveal that the optical characteristics of the two-dimensional Gaussian quantum dot system are considerably influenced by the strength of the intense laser field in addition to structure parameters.

Influence of the intense laser field on optical absorption coefficients and refractive index changes in the double trigonometric quantum wells

In this letter, the effect of the intense laser field on optical properties in the unique double trigonometric quantum wells has been investigated by applying the KH transformation. The Schrdinger equation is solved to obtain the energy levels and the wave functions of this system. Then the optical absorption coefficients (OACs) and refractive index changes (RICs) are calculated through the scheme of the compact density-matrix formalism. The results show that the OACs and RICs undergo a blue-shift first, followed by a red-shift, as the intensity of the laser field is enhanced. Furthermore, features of various transition total OACs are also discussed, which are also affected by the laser field.