When should I consider using a holographic diffuser?

Holographic diffusers, a type of Holographic Optical Element (HOE), give a higher transmission of light than typical ground or opal glass diffusers. Because of their design, holographic diffusers also offer a more even distribution of light. They also give the added bonus of allowing the user to control the amount of diffusion by selecting the diffusion angle and aspect ratio. Holographic diffusers can increase transmission efficiency to greater than 90% from filament lamps, LEDs, arc lamps, and other sources. It is important to note that diffusing angles listed for these diffusers are for collimated light and angular divergence will vary for different incidence angles. Although they do offer better diffusion and control, they tend to be priced higher than typical ground or opal glass diffusers.