New application of photo-thermo-refractive glass (PTR) named “holographic prism” is presented. In the holographic prism angles between directions are set by the holograms which create “fan” of signal beams. This kind of prism creates several signal beams which are equal to the reflections from facets of the conventional silica prism. Implementation of PTR glass as a holographic medium for this device brought us several advantages and new features. First it leads to decrease in overall size of the prism that positively affects the identification process of the beam's crosspoint. Thus, it increases sensitivity and accuracy of the measure. Second, greater value of the refractive index change in PTR glass in comparison with calcium fluoride crystal allows us to increase quantity of the recorded reference beams for the measure which leads to sensitivity increase. During this work, it was found that with uneven exposures the refractive index distribution between the gratings is proportional to their irradiation. Also, we demonstrated various geometries of diffraction responses for a new modification of the holographic prism, with two perpendicular "fans".
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