Patent ID: 9188784
Filing Date: 2015-11-17
Classification: G01N,G02B,G03F

Abstract:
1. A device for shaping a light beam to have an intensity distribution having at least one point of substantially zero intensity, said device having a beam axis, the device comprising a plurality of transparent plates of varying thickness, wherein said plates are disposed substantially in a plane, so that said plates are arrayed in relation to said axis, so that different portions of said beam pass through different transparent plates, wherein a first transparent plate has a first composition and wherein a second transparent plate has a second composition different from the first composition of the first transparent plate, and wherein said compositions and thicknesses of said plates are chosen such that at any wavelength in a wavelength range of at least several tens of nanometers said beam portions experience particular phase delays in passing through their corresponding plates, such that said particular phase delays cause said beam portions to interfere at said at least one point to produce a substantially zero intensity.