Absorption switching and bistability in InSb

For a temperature-dependent absorption appropriate to a thermally shifting semiconductor band-edge at low temperatures, or to a broadening Urbach tail at high temperatures, the criteria for pure absorptive bistability are shown to be (i) α 0 L 2.7 T 0. L is the sample thickness, α 0 the initial absorption coefficient, A is a thermal constant, T 0 is the temperature coefficient of the absorption and I 0 is the incident irradiance. Observation of absorption switching and of purely absorptive bistability under such conditions is reported for InSb near 77 K.