Thank for your help
and sry for my late respond

Please take a look at the picture of this document: http://discovery.bits-pilani.ac.in/~raj/fresnel-biprism.pdf
[url=http://discovery.bits-pilani.ac.in/~raj/fresnel-biprism.pdf]http://discovery.bits-pilani.ac.in/~raj/fresnel-biprism.pdf[/url]


d    , d'   , a(1)   ,  a(2){  ,    , wavelength of the light  must be adjust able


and if is possible the simulate must show  i: The fringe width  and  a: ( distance betwen s(1) and s(2) )

By the way it must show the diffraction


Best Regards