Lens design with reduced sensitivity to thermally induced stress birefringence

In optical systems required to maintain the polarization states of the transiting light, mechanically induced stress birefringence can degrade performance, at least locally altering polarization phase and ultimately reducing polarization contrast. Although thermally induced stress birefringence can cause similar problems in imaging systems bearing high optical flux, appropriate design approaches to resolve this problem have been lacking. This paper first develops criteria to select optical glasses with reduced sensitivity to thermally induced stress birefringence. The design of projection lenses using the resulting thermal stress desensitized reduced glass list is then discussed, as is the application of such lenses in laser projection systems.