Can gratings with different dispersion angles be made?

VPHGs can be made at almost any angle. Dickson Gratings® perform in narrow angular ranges, it is this limitation that allows them to work as well as they do. There are however two classes of realizable Dickson Gratings® with the first working near a half angle of 46.5 degrees in air and the other working at internal angles too high to escape from a flat substrate which must therefore be used with prisms. This latter design is termed the Dickson Grism® and has nearly TWICE the dispersion per pass of a Dickson Grating®. In January of 2005, we delivered samples of our latest high dispersion product, the Dickson 1350® for 1525-1565nm which produces >2 times the dispersion of a 940 lpmm Dickson Grating®.