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...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,V1,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-densitymatrix 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 ofη,V1,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.展开更多
The dispersions of the top interface optical phonons and the side interface optical phonons in cylindrical quantum dots are solved by using the dielectric continuum model. Our calculation mainly focuses on the frequen...The dispersions of the top interface optical phonons and the side interface optical phonons in cylindrical quantum dots are solved by using the dielectric continuum model. Our calculation mainly focuses on the frequency dependence of the IO phonon modes on the wave-vector and quantum number in the cylindrical quantum dot system.Results reveal that the frequency of top interface optical phonon sensitively depends on the discrete wave-vector in z direction and the azimuthal quantum number, while that of the side interface optical phonon mode depends on the radial and azimuthal quantum numbers. These features are obviously different from those in quantum well, quantum well wire,and spherical quantum dot systems. The limited frequencies of interface optical modes for the large wave-vector or quantum number approach two certain constant values, and the math and physical reasons for this feature have been explained reasonably.展开更多
The properties of polar optical phonon vibrations in a quasi-zero- dimensional （QOD） anisotropic wurtzite cylindrical quantum dot （QD） are analyzed based on the dielectric continuum model and Loudon＇s uniaxial cr...The properties of polar optical phonon vibrations in a quasi-zero- dimensional （QOD） anisotropic wurtzite cylindrical quantum dot （QD） are analyzed based on the dielectric continuum model and Loudon＇s uniaxial crystal model. The analytical electrostatic potentials of the phonon vibrations in the systems are deduced and solved exactly. The result shows that there exist four types of polar mixing optical phonon modes in the QOD wurtzite cylindrical QD systems. The dispersive equations and electron-phonon coupling function for the quasi-confined-half-space （QC-HS） mixing modes are derived and discussed. It is found that once the radius or the height of the QD approach infinity, the dispersive equations of the QC-HS mixing modes in the QOD cylindrical QD can naturally reduce to those of the QC and HS modes in Q2D QWs or Q1D QWWs systems. This has been analyzed reasonably from both of physicM and mathematical viewpoints.展开更多
The density matrix approach has been employed to investigate the opticalnonlinear polarization in a single semiconductor quantum dot(QD).Electron states are considered tobe confined within a quantum dot with infinite ...The density matrix approach has been employed to investigate the opticalnonlinear polarization in a single semiconductor quantum dot(QD).Electron states are considered tobe confined within a quantum dot with infinite potential barriers.It is shown,by numericalcalculation,that the third-order nonlinear optical susceptibilities for a typical Si quantum dot isdependent on the quantum size of the quantum dot and the frequency of incident light.展开更多
基金Universidad de Medellín for hospitality and support during their 2019–2020 sabbatical stayMexican CONACYT through research Grant A1-S-8218。
文摘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,V1,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-densitymatrix 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 ofη,V1,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.
文摘The dispersions of the top interface optical phonons and the side interface optical phonons in cylindrical quantum dots are solved by using the dielectric continuum model. Our calculation mainly focuses on the frequency dependence of the IO phonon modes on the wave-vector and quantum number in the cylindrical quantum dot system.Results reveal that the frequency of top interface optical phonon sensitively depends on the discrete wave-vector in z direction and the azimuthal quantum number, while that of the side interface optical phonon mode depends on the radial and azimuthal quantum numbers. These features are obviously different from those in quantum well, quantum well wire,and spherical quantum dot systems. The limited frequencies of interface optical modes for the large wave-vector or quantum number approach two certain constant values, and the math and physical reasons for this feature have been explained reasonably.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 60276004 and 60390073 and the Natural Science Foundation of Guangzhou Education Bureau under Grant No. 2060
文摘The properties of polar optical phonon vibrations in a quasi-zero- dimensional （QOD） anisotropic wurtzite cylindrical quantum dot （QD） are analyzed based on the dielectric continuum model and Loudon＇s uniaxial crystal model. The analytical electrostatic potentials of the phonon vibrations in the systems are deduced and solved exactly. The result shows that there exist four types of polar mixing optical phonon modes in the QOD wurtzite cylindrical QD systems. The dispersive equations and electron-phonon coupling function for the quasi-confined-half-space （QC-HS） mixing modes are derived and discussed. It is found that once the radius or the height of the QD approach infinity, the dispersive equations of the QC-HS mixing modes in the QOD cylindrical QD can naturally reduce to those of the QC and HS modes in Q2D QWs or Q1D QWWs systems. This has been analyzed reasonably from both of physicM and mathematical viewpoints.
基金Supported by the Committee of Science and Tech nology of Wuhan(1320017010121)
文摘The density matrix approach has been employed to investigate the opticalnonlinear polarization in a single semiconductor quantum dot(QD).Electron states are considered tobe confined within a quantum dot with infinite potential barriers.It is shown,by numericalcalculation,that the third-order nonlinear optical susceptibilities for a typical Si quantum dot isdependent on the quantum size of the quantum dot and the frequency of incident light.
