OPTICAL DESIGNS FOR ZERO ORDER REDUCTION
Apparatus for projecting a pattern includes a first diffractive optical element (DOE) configured to diffract an input beam so as to generate a first diffraction pattern on a first region of a surface, the first diffraction pattern including a zero order beam. A second DOE is configured to diffract the zero order beam so as to generate a second diffraction pattern on a second region of the surface such that the first and the second regions together at least partially cover the surface.
1 - 17 . (canceled)
18 . Apparatus for projecting a pattern, comprising:
a diffractive optical element (DOE) configured to diffract an input beam having a wavelength so as to generate a diffraction pattern comprising a zero order beam; and
a narrow-band filter, which is tuned to the wavelength of the input beam and is positioned with respect to the DOE so as to cause the diffraction pattern, absent the zero order beam, to impinge on a region of a surface.
19 . The apparatus according to claim 18 , wherein the filter comprises an interference filter.
20 . The apparatus according to claim 18 , wherein the filter comprises a grating.
21 - 22 . (canceled)
23 . A method for projecting a pattern, comprising:
diffracting an input beam having a wavelength with a diffractive optical element (DOE) so as to generate a diffraction pattern, which comprises a zero order beam;
positioning a narrow-band filter, which is tuned to the wavelength of the input beam, with respect to the DOE so as to cause the diffraction pattern, absent the zero order beam, to impinge on a region of the surface.