Parallel light rays through a sprial wave plate diverge?

[Spinnor]

Do parallel light rays diverge if ever so slightly upon exiting a spiral wave plate? See image below.

Images from,

https://www.google.com/search?q=spiral+phase+plate&safe=off&sa=X&es_sm=122&biw=1360&bih=649&tbm=isch&tbo=u&source=univ&ei=xEGDVcaKFYLV-AHZop_IAw&ved=0CC0QsAQ#imgrc=V_wYVTQHs9_JcM%3A;MIMazroQRD_VYM;http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2F1%2F1f%2FSpiral-phase-plate.png;http%3A%2F%2Fen.wikipedia.org%2Fwiki%2FAngular_momentum_of_light;1047;382

If there is divergence does that change the angular mementum of the light?

Thanks for any help!

 

[Omega0]

If there is no interface between those glas parts where would you expect any special things but a straight beam?
It makes no sense from the very beginning.

 

[Spinnor]

If there is no interface between those glas parts where would you expect any special things but a straight beam?
It makes no sense from the very beginning.

The first image above seems to show a typical light ray bending.

 

[Omega0]

The first image above seems to show a typical light ray bending.

Come on... the symmetry is circular and waves here are as I expect them...it seems to be homogenieous material ... you can find silly ways to bend light but in the end you will have nothing but light, may be polarized. From symmetry reasons the outcouming is nonsense. If it is homgeneous stuff.
May be harsh critics but I think Spinnor will report about it.