Optical: systems and elements – Diffraction – From grating
Reexamination Certificate
2006-05-23
2006-05-23
Assaf, Fayez G. (Department: 2872)
Optical: systems and elements
Diffraction
From grating
C359S572000, C359S576000, C359S359000, C359S361000
Reexamination Certificate
active
07050237
ABSTRACT:
An asymmetric-cut multilayer diffracts EUV light. A multilayer cut at an angle has the same properties as a blazed grating, and has been demonstrated to have near-perfect performance. Instead of having to nano-fabricate a grating structure with imperfections no greater than several tens of nanometers, a thick multilayer is grown on a substrate and then cut at an inclined angle using coarse and inexpensive methods. Effective grating periods can be produced this way that are 10 to 100 times smaller than those produced today, and the diffraction efficiency of these asymmetric multilayers is higher than conventional gratings. Besides their ease of manufacture, the use of an asymmetric multilayer as a spectral purity filter does not require that the design of an EUV optical system be modified in any way, unlike the proposed use of blazed gratings for such systems.
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Assaf Fayez G.
The Regents of the University of California
Thompson Alan H.
Wooldridge John P.
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