Bin Chen

Guangzhou University, Shengcheng, Guangdong, China

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Publications (11)17.17 Total impact

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    ABSTRACT: The optical absorption coefficients and the changes in the refractive index in GaAs/AlGaAs parabolic quantum dots(QDs) with applied electric and magnetic fields are studied in detail. Analytical expressions for the linear and nonlinear intersubband absorption coefficients and refractive index changes are obtained by using a compact density matrix approach and an iterative procedure. Finally, the calculated results show the incident optical intensity, the frequencies of the confined potential of the QDs and the applied electric and magnetic fields have a great influence on the optical absorption coefficients and refractive index changes in this system.
    Superlattices and Microstructures 02/2010; 47(2):325-334. · 1.98 Impact Factor
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    ABSTRACT: An approach for dot pattern designing on the light guide plate of backlight module is proposed in this paper. The proposed approach employs molecular potential energy model to generate random-dot patterns for light guide designed for backlight systems. The methods of developing dot patterns are various. We chose AutoCAD-VBA programme method for its visible interface. The algorithm can be divided into two steps: Firstly, an AutoCAD-VBA programme is compiled to generate random initial dot patterns, which contains 69 091 points. Secondly, a variable equilibrium distances system are found by the Mathematica software to fine tune distances among those points. At last, we have derived dot patterns which can satisfy the uniformity luminance requirement demanded by liquid-crystal displays, testing results show that the optical uniformity can reach 89.3%.
    Journal of Display Technology 01/2010; 6(5):166-169. · 1.66 Impact Factor
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    ABSTRACT: The second harmonic generation (SHG) in the asymmetric double triangular quantum wells (DTQWs) is investigated theoretically. The dependence of the SHG coefficient on the right-well width of the DTQWs is studied, and the influence of the applied electric field on SHG coefficient is also taken into account. The analytical expression of the SHG coefficient is analyzed by using the compact density-matrix approach and the iterative method. Finally, the numerical calculations are presented for the typical GaAs/AlxGa1−xAs asymmetric DTQWs. The results show that the calculated SHG coefficient in this coupled system can reach the magnitude of 10−5 m/V, 1–2 orders of magnitude higher than that in step quantum well, and that in double square quantum wells. Moreover, the SHG coefficient is not a monotonic function of the right-well width, but has complex relationship with it. The calculated results also reveal that an applied electric field has a great influence on the SHG coefficient. Applying an appropriate electric field to a DTQW with a wider right well can induce a sharper peak of the SHG coefficient due to the double-resonant enhancement.
    Superlattices and Microstructures 03/2009; 45(3):125–133. · 1.98 Impact Factor
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    ABSTRACT: The optical rectification (OR) in the asymmetric coupled quantum wells (ACQWs) is calculated theoretically. The dependence of the OR on the width of the right-well and the barrier is studied. The analytical expression of the optical rectification coefficient is obtained by using the compact density-matrix approach and the iterative method, and the numerical calculations are presented for a typical GaAs/AlxGa1 − xAs ACQW. The results obtained show that the OR efficient can reach the magnitude of 10−4 m/V in this ACQW system, which is 1–2 orders higher than that in single quantum systems. Moreover, the OR coefficient is strongly dependent on the widths of the barrier and the right-well of the ACQWs. An appropriate choice for the width of the barrier and the right-well of the ACQWs can induce a larger OR coefficient.
    Physics Letters A 02/2009; 373(7):795-798. · 1.63 Impact Factor
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    ABSTRACT: Third-harmonic generation (THG) for cubical quantum dots (CQDs) with an applied electric field is theoretically investigated in the framework of the compact-density-matrix approach and an iterative method. The confined wave functions and energies of electrons in the CQDs are calculated in the effective-mass approximation. Numerical calculations are presented for typical GaAs/AlAs CQDs. The results demonstrate that the THG strongly depends on the length of the CQDs and the magnitude of the electric field. Also, the peaks shift towards the higher energy region with increasing electric field.
    Superlattices and Microstructures 01/2009; 46(4):672-678. · 1.98 Impact Factor
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    ABSTRACT: The third-harmonic generation (THG) in asymmetric coupled quantum wells (ACQWs) for different values of the well parameter Δ and width of barrier (WB) are theoretically studied. The analytical expression of the third-harmonic generation is derived by using the compact density-matrix approach and the iterative method. Finally, the numerical calculations are presented for typical GaAs/AlxGa1−xAs asymmetric coupled quantum wells. Results obtained show that the third-harmonic generation in the asymmetric coupled quantum wells can be importantly modified by the parameter Δ and WB. Moreover, third-harmonic generation also depends on the relaxation rate of the asymmetric coupled quantum wells.
    Superlattices and Microstructures 01/2009; 45(1):8-15. · 1.98 Impact Factor
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    ABSTRACT: The intersubband optical absorption in cylindrical quantum dot quantum well (QDQW) for different sizes of QDQW is theoretically studied. The analytical expression of the absorption coefficient is derived by using the compact density-matrix approach and the iterative method. And the numerical calculations are presented for a typical GaAs/AlGaAs QDQW. The results obtained show that the optical absorption coefficient in the QDQW can be importantly modified by size of shell well. Moreover, they also show that the optical absorption is strongly dependent on the incident optical intensity.
    International Journal of Modern Physics B 01/2009; 23(14):3179-3186. · 0.46 Impact Factor
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    ABSTRACT: The optical rectification (OR) coefficient for cubical quantum dots (CQDs), with an applied electric field is theoretically investigated in the framework of the compact-density-matrix approach and an iterative method. The confined wave functions and energies of electrons in the CQDs are calculated in the effective-mass approximation. Numerical calculations are presented for typical GaAs/AlAs CQDs. The results show that the calculation for OR coefficient in the CQDs system can reach a magnitude of 10-4m/V, two orders higher than that in the spherical quantum dots system. The OR coefficient strongly depends on the length of CQDs and the magnitude of electric field. And the peak shifts to the aspect of high energy when considering the electric field.
    Physica B Condensed Matter 01/2009; 404(16):2332-2335. · 1.28 Impact Factor
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    ABSTRACT: The linear and the third-order nonlinear optical absorptions in the asymmetric double triangular quantum wells (DTQWs) are investigated theoretically. The dependence of the optical absorption on the right-well width of the DTQWs is studied, and the influence of the applied electric field on the optical absorption is also taken into account. The analytical expressions of the linear and the nonlinear optical absorption coefficients are obtained by using the compact density-matrix approach and the iterative method. The numerical calculations are presented for the typical GaAs/AlxGa1−xAs asymmetric DTQWs. The results show that the linear as well as the nonlinear optical absorption coefficients are not a monotonous function of the right-well width, but have complex relationships with it. Moreover, the calculated results also reveal that applying an electric field to the DTQWs with a thinner right-well can enhance the linear optical absorption but has no prominent influence on the nonlinear optical absorption. In addition, the total optical absorption is strongly dependent on the incident optical intensity.
    Solid State Communications 01/2009; 149(7):310-314. · 1.53 Impact Factor
  • Chinese Journal of Physics- Taipei- 01/2009; 47. · 0.48 Impact Factor
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    ABSTRACT: The second harmonic generation (SHG) in the asymmetric coupled quantum wells (ACQWs) is studied theoretically for different widths of the right-well and the barrier. The analytical expression of the SHG susceptibility is deduced by using the compact density matrix approach and the iterative method. Numerical calculations are presented for typical GaAs/AlxGa1−xAs ACQWs. The results show that the calculated SHG susceptibility in this coupled system can reach a magnitude of 10−5 m V−1, 1–2 orders higher than that in single quantum systems. Moreover, the SHG susceptibilities are not monotonic functions of the widths of the right-well and the barrier, but have complex relationships with them. The calculated results also reveal that by adjusting the widths of the right-well and the barrier respectively, a set of optimal structural parameters can be found for obtaining a strong SHG susceptibility.
    Journal of Physics Condensed Matter 05/2008; 20(25):255214. · 2.22 Impact Factor