Reflection of short polarized optical pulses from periodic and aperiodic multiple quantum well structures

TL;DR

This paper investigates how short polarized optical pulses reflect from various quantum well structures, revealing how structure design influences pulse shape, polarization conversion, and the transition between superradiant and photonic-crystalline regimes.

Contribution

It provides a comparative analysis of periodic, Fibonacci, and gradient quantum well structures, highlighting their effects on pulse reflection and polarization conversion.

Findings

Reflected pulse shape depends on structure length and design.

Pulse duration varies non-monotonically with number of wells.

Gradient structures are more efficient for polarization conversion.

Abstract

We study the reflection of polarized optical pulses from resonant photonic structures formed by periodic, Fibonacci, and gradient sequences of quantum wells. The form and polarization of the reflected pulse are shown to be determined by the structure design and optical length. In structures with periodic quantum well arrangement, the response to ultrashort pulse is an optical signal with a sharp rise followed by an exponential decay or Bessel beats depending on the structure length. The duration of reflected pulses non-monotonically depends on the number of quantum wells reaching the minimum for a certain structure length which corresponds to the transition from superradiant to photonic-crystalline regime. We also study the conversion of pulse polarization in the longitudinal external magnetic field which splits the exciton resonance. Comparing periodic, Fibonacci, and gradient structures we show that the latter are more efficient for the conversion from linear to circular polarization.