Reconfigurable compound diffraction grating
First Claim
1. An array of reconfigurable diffraction gratings comprising at least one diffraction grating, each said diffraction grating comprising:
- a plurality of substantially parallel diffraction beams further comprising a plurality of stationary beams and a plurality of deflectable beams;
in an initial position, said stationary beams substantially residing within a stationary beam plane and said deflectable beams substantially residing within a deflectable beam plane slightly elevated with respect to said stationary beam plane; and
said deflectable beams occupying regular, periodic positions among said diffraction beams and separated from one another within each such period by at least one successive stationary beam;
a plurality of lower electrode extension beam means each associated with, substantially parallel to, and beneath, one of said deflectable beams; and
voltage differential means applying a selected voltage differential between each of said lower electrode extension beam means and its associated deflectable beam thereby moving said deflectable beams and hence said deflectable beam plane by a selected distance, from said initial position.
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Accused Products
Abstract
A reconfigurable compound diffraction grating is fabricated using microelectomechanical systems (MEMS) technology. The compound grating structure can be viewed as the superposition of two separately configured gratings. A common lower electrode is placed beneath selected beam elements, known as deflectable beams, to achieve the desired grating configuration (i.e. every other, every third, every fifth, etc.) of the beams in the primary grating. These deflectable beams alone comprise a secondary, lower resolution grating structure. The beam elements are linked to a common upper electrode. Voltage applied across the electrodes creates an electrostatic force that pulls the selected beams down toward the underlying electrode. Changing the vertical position of the selected beams with respect to the other stationary beams presents a different ruling spacing distribution to the incoming radiation. By changing this distribution, the diffracted power among individual diffraction orders of the wavelengths is altered. Controlling the diffracted signal in this way allows for specific diffraction passbands to be fixed on a particular detector or a particular area of a detector. Automated adjustments to the rulings can be very rapidly, which would significantly simplify and reduce the time necessary for complete spectral analysis previously achieved by mechanical movement of diffraction gratings.
122 Citations
26 Claims
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1. An array of reconfigurable diffraction gratings comprising at least one diffraction grating, each said diffraction grating comprising:
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a plurality of substantially parallel diffraction beams further comprising a plurality of stationary beams and a plurality of deflectable beams;
in an initial position, said stationary beams substantially residing within a stationary beam plane and said deflectable beams substantially residing within a deflectable beam plane slightly elevated with respect to said stationary beam plane; and
said deflectable beams occupying regular, periodic positions among said diffraction beams and separated from one another within each such period by at least one successive stationary beam;a plurality of lower electrode extension beam means each associated with, substantially parallel to, and beneath, one of said deflectable beams; and voltage differential means applying a selected voltage differential between each of said lower electrode extension beam means and its associated deflectable beam thereby moving said deflectable beams and hence said deflectable beam plane by a selected distance, from said initial position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for reconfiguring an array of reconfigurable diffraction gratings comprising at least one diffraction grating, comprising the steps of, for each said diffraction grating of said grating array:
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applying a selected voltage differential between a plurality of substantially parallel deflectable beams and a plurality of lower electrode extension beam means each associated with, substantially parallel to, and beneath, one of said deflectable beams; and moving thereby, said deflectable beams and hence a deflectable beam plane within which said deflectable beams reside, by a selected distance, from an initial position slightly elevated with respect to a plurality of stationary beams substantially residing within a stationary beam plane; a plurality of substantially parallel diffraction beams comprising said plurality of deflectable beams and said plurality of stationary beams; and said deflectable beams occupying regular, periodic positions among said diffraction beams and being separated from one another within each such period by at least one successive stationary beam. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification