Nonlinear Far-Infrared Magnetoabsorption and Optically Detected Magnetoimpurity Effect in $n$-GaAs

Measurements have been made of cw nonlinear far-infrared magnetoabsorption in pure, partially compensated $n$-GaAs. A new optical observation of the magnetoimpurity resonance has been demonstrated. Analysis in terms of a three-level model gives effective lifetimes of ∼0.5 μs "off resonance" and 30 ns "on resonance," implying the possibility of laser action in the former case.