J4 ›› 2011, Vol. 28 ›› Issue (4): 473-482.

• Nonlinear Optics • Previous Articles     Next Articles

Excitonic effects on third-harmonic generation in quantum wells via a fractional-dimentional space approach

YU Fengmei1, LI Wei1,GUO Kangxian2   

  1. 1 Information College, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; 
    2 Department of Physics, College of Physics and Electronic Engineering, Guangzhou University, Guangzhou 510006, China 
  • Received:2011-01-04 Revised:2011-04-11 Published:2011-07-28 Online:2011-07-06
  • Supported by:

    Supported by Foundation for Distinguished Young Talents in Higher Education of Guangdong ( LYM08068) and Science and Technology Plan Projects in Guangdong Province ( 2010A080802002, 2010B080704002, 2010B090400130)

Abstract:

Exciton effects on the third-harmonic generation in GaAs/AlGaAs infinite and finite square quantum wells are calculated within the framework of the fractional-dimensional space approach. The wave functions and bound energies are obtained as functions of spatial dimensionality and the dimension is a function of the well width. For an infinite confining potential the dimension (D) has a transition from the 3D limit to the 2D limit when the well width decreases. However, in a finite well, when the well width decreases below a given value, the dimension increases. The analytical expression of the third-harmonic generation is described using the compact density method and the iterative procedure. The numerical results show that the third-harmonic generation coefficient with considering exciton effects is 40% greater than the one without considering exciton effects and it is very sensitively dependent on the exciton confinement. In addition, the smaller the relaxation constant is, the larger the third-harmonic generation will be.

Key words: nonlinear optics, third-harmonic generation, fractional-dimensional space, exciton effects, quantum wells

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