Optically stimulated electron paramagnetic resonance: simplicity, versatility, information content

TL;DR

This paper introduces a simple, versatile technique called optically stimulated electron paramagnetic resonance (OSEPR) that provides detailed information about magnetic and optical properties of various systems, including rare-earth ions, semiconductors, and atomic cesium.

Contribution

The paper proposes and investigates a new OSEPR technique, demonstrating its ability to analyze systems typically not studied with this method and to estimate both magnetic and optical transition parameters.

Findings

Demonstrated OSEPR spectra for Nd$^{3+}$ ions and GaAs.

Observed optical nonlinearity in cesium enabling Rabi frequency estimation.

Interpreted experimental effects with a theoretical model.

Abstract

A simple technique for observing optically stimulated electron paramagnetic resonance (OSEPR) is proposed and investigated. The versatility and information content of the described technique is demonstrated by the example of the OSEPR spectra of systems that are unpopular for this type of spectroscopy: a crystal with rare-earth ions Nd$^{3+}$ and a doped semiconductor GaAs. In addition, the OSEPR spectrum of atomic cesium is presented, in which an optical nonlinearity is observed that makes it possible to estimate the Rabi frequency for the relevant optical transition. The effects observed in the described experiments (switching of peaks to dips, light-induced splitting of the OSEPR lines, and the appearance of a spectral feature at the double-Larmor frequency) are interpreted using the model proposed in the theoretical part of the work. The suggested interpretation shows the possibility of using the described OSEPR technique to estimate not only `magnetic' parameters of the model Hamiltonian (g-factors, spin relaxation times), but also the Rabi frequencies characterizing optical transitions.