Formation of Transmissionlike Reflection Fringes

Abstract

It is shown that certain combinations of reflectances and transmittances of a pair of semireflecting films will produce transmissionlike reflection fringes under phase-angle conditions normally associated with reflection-type fringes. Some of these combinations are precluded by the conservation of energy. The familiar restrictions r2+t2≤1,r′2+t2≤1 on the transmittance and forward and backward reflectances of a film must be supplemented by the condition (1+r′) (1-r)≤t2.