|What is a VPH Grating?
VPH transmission gratings work much like conventional surface relief reflection gratings, except in transmission. They are periodic phase structures, whose fundamental purpose is to diffract different wavelengths of light from a common input path into different angular output paths. The phase of incident light is modulated as it passes through a volume of the periodic phase structure, hence the term “Volume Phase”. This is in contrast to a conventional grating, in which the depth of a surface relief pattern modulates the phase of the incident light.
Every VPH grating is a holographic master so there is no replication degradation from unit to unit or over time, unlike other gratings. The consistency of these gratings provide demonstrable benefits for the systems integrator.