The new diffractive double-spot elements from Holo/OR have an efficiency of 97%; previous standard versions only achieved 81%.
High-Efficiency Double-Spot (HEDS)
Diffractive beam splitters split the incoming beam into beams with equal properties. The intensity of all partial beams corresponds approximately to the total intensity of the incoming beam. For the new “high-efficiency double-spot DOEs,” this means that each partial beam is >48% of the total intensity!
Advantage: No Higher Diffraction Orders
In previous versions, part of the light had higher diffraction orders; this is shown in blue in the graph. The HEDS elements have higher diffraction orders that are negligibly small: this is an advantage in critical applications. HEDS are available for wavelengths from 193nm to 10.6µm.
High efficiency is achieved through a novel design that requires the centering of the HEDS in the beam path. When shifted, the spot shape and total efficiency of the element remain unchanged; however, the power distribution between both spots changes. This property can be used advantageously for the fine adjustment of the split ratio; for example, instead of a 50:50 ratio, a ratio of 47:53 could be set. These elements are used, for example, in lithography, perforation, laser cutting, and other material processing applications.