Magnetic Field Shift of Optically Pumped Stimulated Emission in High-Purity GaAs

Optically pumped stimulated emission in high-purity GaAs shifts toward the blue with magnetic field as $\frac{1}{2}\hslash {({\omega }_p^2+{\omega }_c^2)}^{\frac{1}{2}}$, where ${\omega }_p$ is the plasma frequency ${\left(\frac{4\pi n{e}^2}{\epsilon m^{*}}\right)}^{\frac{1}{2}}$ and ${\omega }_c$ the cyclotron frequency $\frac{\mathrm{eB}}{m^{*}c}$. The possibility of exciton-exciton recombination is thus excluded. The quantitative agreement between the experimental shift toward the blue and the increase in the zero-point energy of the dominant hybrid plasmon mode confirms the importance of plasmaron coupling in this common laser material.