Anisotropy and nonlinearity in superlattices

Abstract

This paper uses analytical expressions for the nonlinear optical absorption of superlattices by treating them as anisotropic media. The controllable system shows that the nonlinearities increase with anisotropy suggesting that strongly anisotropic materials such as those used for solar cells may also be useful for nonlinear optical applications.

Anisotropy and nonlinearity in superlattices II

“…Efficient numerical methods used here have been successfully applied to both inter-subband (Pereira and Faragai 2014;Pereira 2007Pereira , 2008Pereira , 2011Pereira et al 2007;Pereira and Tomić 2011) and inter-band transitions (Grempel et al 1996;Pereira et al 1994;Pereira and Henneberger 1997;Chow et al 1992) in quantum wells and superlattices. For completeness, we repeat here the main equations of Pereira (2016) for a guide to the reader, by starting with the interband polarization that has been used to describe superlattices as an effective anisotropic 3D material (Pereira 1995),…”

“…In other words, isolated quantum wells should not be addressed by this method. This paper extends and complements the study in Pereira (2016) with different well widths and a more detailed analysis of the population inversion and is organized as follows: first, the main equations used are summarized. Next, numerical applications for GaAs/AlGaAs superlattices are given and a short summary follows.…”

Luminescence and absorption in short period superlattices

“…The next step is to combine the Kubo-Martin-Schwinger (KMS) relation under the form derived in Ref. [29]…”

Analytical Expressions for Numerical Characterization of Semiconductors per Comparison with Luminescence

“…The interplay of homogeneous versus inhomogeneous broadening at low and high temperatures are described, together with the relevance of many body effects, which are in very good agreement with experiments [ 10 , 11 , 12 , 13 ]. A similar set of equations was also used to study nonlinearities in GaAs–AlGasAs and GaAsN–AlGaAs superlattices [ 14 , 15 , 16 ]. The superlattice case is particularly noteworthy for room temperature GHz nonlinear multiplication into the THz range [ 17 , 18 ].…”

“…This paper has two objectives: to show hitherto unpublished details of the mathematical steps that lead to the equations used in Refs. [ 7 , 8 , 9 , 14 , 15 , 16 ], and to draw a bridge between the luminescence and nonlinear absorption calculations in superlattices. It is organized as follows: the main steps involving manipulations of hypergeometric functions that characterize the solution of the Hulthén potential problem are delivered.…”