Grating device with high diffraction efficiency
First Claim
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1. Grating device for efficient operation at an angle of incidence different from a blaze angle, the grating device comprising:
- a grating structure having grating facets and a grating period, a multilayer dielectric coating disposed at least on the grating facets and having layers alternating between a first and second refractive index, wherein half the grating period is substantially identical to the wavelength of the diffracted light beam times the order of diffraction, and wherein the optical thickness of two successive layers of the multilayer dielectric coating at the angle of incidence is selected to be substantially identical to one half of the wavelength of the diffracted light beam.
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Abstract
A grating structure with a dielectric coating is disclosed that operates efficiently away from the blaze angle in low order with a high diffraction efficiency and high wavelength dispersion. Such grating structure can be employed in Littrow configuration to provide, for example, cavity feedback in excimer lasers.
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Citations
10 Claims
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1. Grating device for efficient operation at an angle of incidence different from a blaze angle, the grating device comprising:
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a grating structure having grating facets and a grating period, a multilayer dielectric coating disposed at least on the grating facets and having layers alternating between a first and second refractive index, wherein half the grating period is substantially identical to the wavelength of the diffracted light beam times the order of diffraction, and wherein the optical thickness of two successive layers of the multilayer dielectric coating at the angle of incidence is selected to be substantially identical to one half of the wavelength of the diffracted light beam. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. Method for operating an optical grating device in low diffraction order at an angle of incidence substantially different from a blaze angle, the method comprising:
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producing a grating structure with the selected blaze angle, with a grating period being substantially identical to the wavelength of the diffracted light beam times the order of diffraction, and applying to the grating structure a multilayer dielectric coating having layers alternating between a first and second refractive index, wherein the optical thickness of two successive layers of the multilayer dielectric coating at the angle of incidence is selected to be approximately identical to one half of the wavelength of the diffracted light beam. - View Dependent Claims (9, 10)
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Specification