New approach to study light-emission of periodic structures. Unveiling novel surface-states effects

TL;DR

This paper introduces a precise method for analyzing the optical response of periodic structures, revealing new surface-state effects and explaining previously unexplained spectral features.

Contribution

It presents a novel approach using superlattice eigenfunctions to derive new optical transition rules and accurately reproduce complex spectral phenomena.

Findings

Forbidden transitions become allowed under new rules

Surface states produce distinctive optical signatures

High-resolution spectra are fully explained and matched

Abstract

An accurate approach to calculate the optical response of periodic structures is proposed. Using the genuine superlattice eigenfunctions and energy eigenvalues, the eigenfunctions parity symmetries, the subband symmetries and the detached surface energy levels, we report new optical-transition selection rules and explicit optical-response calculations. Observed transitions that were considered forbidden, become allowed and interesting optical-spectra effects emerge as fingerprints of intra-subband and surface states. The unexplained groups and isolated narrow peaks observed in high resolution blue-laser spectra, by Nakamura et al., are now fully explained and faithfully reproduced