Nonlinear optical rectification in asymmetric double triangular quantum wells

• Published in: The European physical journal. B, Condensed matter physics Condensed matter physics, 2008-11, Vol.66 (2), p.227-233
• Main Authors: Chen, B., Guo, K.-X., Wang, R.-Z., Zheng, Y.-B., Li, B.
• Format: Article
• Language: English
• Subjects: Complex Systems; Condensed Matter Physics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Fluid- and Aerodynamics; Mesoscopic and Nanoscale Systems; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Physics; Physics and Astronomy; Quantum wells; Solid State Physics
• ISSN: 1434-6028; 1434-6036
• DOI: 10.1140/epjb/e2008-00398-y

The nonlinear optical rectification (OR) in the asymmetric double triangular quantum wells (DTQWs) is investigated theoretically. The dependence of OR on the right-well width of the DTQWs is studied, and the influence of the applied electric field on OR is also taken into account. The analytical expression of the OR susceptibility is analyzed by using the compact density-matrix approach and the iterative method and the numerical calculations are presented for the typical GaAs/Al x Ga 1-x As asymmetric DTQWs. The results show that the OR susceptibility obtained in this coupled system can reach the magnitude of 10 -3  m/V, 2-3 orders of magnitude higher than that in single quantum systems. Moreover, the OR susceptibility is not a monotonic function of the width of the right well, but has complex relationship with it. The calculated results also reveal that an applied electric field has a great influence on the OR susceptibility. Applying an appropriate electric field to a quasi-symmetric or symmetric DTQW can result in a larger OR susceptibility as compared with that obtained in an optimal asymmetric DTQW without electric field.