An avalanche model for femtosecond optical response

Experiments on Indium Tin Oxide (ITO) have revealed that a relatively broad 200THz pump pulse, roughly 30 cycles in width, can switch ITO from a transparent to a reflecting state within one or two optical cycles, a few Femtoseconds. So far the rapid switching has remained unexplained by theory. Here a very simple bare bones theory explains the key experimental features in terms of an avalanche model suggested by avalanche diodes.