Theory and optimisation of optical bistability in multilayer interference filters

Refractive changes in semiconductors used in optical bistability are induced as a result of excitations generated by intense light levels. To date such excitations have been either electronic (carriers excited to higher energy states) as in InSb or thermal as in ZnSe. Usually such refractive index changes are small and it is necessary to introduce some form of optical feedback in order to obtain a useful change in the output signal. Various configurations which provide optical feedback are examined and the optimisation for low switching power levels is addressed