Theory of nonlinear optical spectroscopy of electron spin coherence in quantum dots

TL;DR

This paper develops a theoretical framework for nonlinear optical spectroscopy of electron spin coherence in quantum dots, enabling measurement of spin relaxation and dephasing times through differential transmission spectra.

Contribution

It introduces a novel theoretical approach to extract spin relaxation and dephasing times from higher-order differential transmission spectra in quantum dots.

Findings

Inverse width of ultra-narrow peak yields $T_1$ (spin relaxation time).

Resonance widths determine $T_2^*$ (inhomogeneous dephasing time).

Hole-burning resonances measure $T_2$ (homogeneous dephasing time).

Abstract

We study in theory the generation and detection of electron spin coherence in nonlinear optical spectroscopy of semiconductor quantum dots doped with single electrons. In third-order differential transmission spectra, the inverse width of the ultra-narrow peak at degenerate pump and probe frequencies gives the spin relaxation time ($T_1$), and that of the Stoke and anti-Stoke spin resonances gives the effective spin dephasing time due to the inhomogeneous broadening ($T_2^*$). The spin dephasing time excluding the inhomogeneous broadening effect ($T_2$) is measured by the inverse width of ultra-narrow hole-burning resonances in fifth-order differential transmission spectra.