Non-Collimated Beam Effects on Gratings

[Neo20]

Hi,

I was wondering what happens when a grating is lightened by non collimated beam.

Could anyone tell me?

Thanks!

 

[Claude Bile]

Your fringe pattern gets blurred because you are illuminating the grating with multiple wave-vectors, rather than just a single incident wave-vector.

The resultant pattern is a convolution between the response of the grating to a single wavevector and the k-spectrum (or angular spectrum) of your incident beam.

Claude.