A time-dependent theory has been developed to model the behavior of doped-InSb, optically bistable etalons operating at room temperature and illuminated by a pulsed CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> laser. Good agreement can be obtained between this semi-empirical theory and experiment. The reduction of switching times to ∼ 1 ns by n-type doping has been demonstrated experimentally.