The most commonly used gratings are generally ruled or etched using either a process involving the mechanical scratching of the surface of a substrate, or exposure of a photoresist layer deposited on a substrate.where the interference pattern produced by two coherent light beams is used to expose the photoresist. The diffraction gratings produced with this process are often called holographic. Both of these processes are used to create a fine, periodic relief pattern on the surface of a blank substrate. Such a relief structure can predictably modify the amplitude and/or phase of the incident light. The superposition of the effects of many such grooves allows for the angular separation of the spectral components of the incident light. Depending on whether the light is reflected from the grooved surface, or transmitted through it, the grating is called either a reflection or transmission diffraction grating.

透射式凝膠光柵（Gel Grating），又稱體相全息衍射光柵（VPH Grating）, 完全不同于傳統的表面凹凸性光柵，凹凸性光柵通過光柵表面的溝槽深度的周期性變化，對光的相位進行調制，從而完成分光，而VPH光柵則通過凝膠層的折射率n的周期性變化對入射光進行調制，完成分光。

Wasatch Photonics 通過自己的專利及相應的商業保密技術，生產增強型體相全息衍射光柵Enhanced-Volume Phase Holographic Gratings (VPHGs) 及全息光學元件 (HOEs). 高性能的光柵可以適合多種應用場合， Dickson Gratings® 光柵是一種專門設計的特殊VPH光柵，具有高色散能力，在偏振S & P都具有高衍射效率，并具有低偏振損耗特點。這種透射型光柵可以使得分光系統更加小巧、結構簡化、減少光學元件的使用，設計靈活，制作簡單。

• 光譜范圍：350nm—2400nm                   
• 波前畸變：典型值1/4wave,更高精度可定制
• 波前均勻性：<1/40 wave RMS                  
• 空間頻率：125 lp/mm —-3600lp/mm