X-ray beamsplitter
First Claim
1. An X-ray beamsplitter comprising:
- a substrate having a window therethrough;
a very thin substantially flat X-ray transparent support membrane deposited on the substrate and extending across the window therein;
a thin multilayer film deposited on the membrane and over the window in the substrate which resonantly reflects, and transmits X-rays of wavelength λ
incident at an angle of θ and
has a periodicity d given by
space="preserve" listing-type="equation">λ
=2 μ
d sin θ
where θ
is the angle of incidence measured from the surface of the beamsplitter and μ
is a predetermined factor which accounts for refractive effects in the multilayer film.
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Accused Products
Abstract
An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5-50 pairs of alternate Mo/Si layers with a period of 20-250 A. The support membrane is 10-200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window.
34 Citations
25 Claims
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1. An X-ray beamsplitter comprising:
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a substrate having a window therethrough; a very thin substantially flat X-ray transparent support membrane deposited on the substrate and extending across the window therein; a thin multilayer film deposited on the membrane and over the window in the substrate which resonantly reflects, and transmits X-rays of wavelength λ
incident at an angle of θ and
has a periodicity d given by
space="preserve" listing-type="equation">λ
=2 μ
d sin θwhere θ
is the angle of incidence measured from the surface of the beamsplitter and μ
is a predetermined factor which accounts for refractive effects in the multilayer film. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for fabricating an X-ray beamsplitter comprising:
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preparing a substrate having front and back sides; depositing an etch stop layer formed of a thin layer of X-ray transparent material on the front and back sides of the substrate; depositing a thin multiplayer film of periodic alternating layers on the layer of X-ray transparent material on the front side of the substrate which resonantly reflects, and transmits X-rays of wavelength λ
incident at an angle θ
;patterning the layer of X-ray transparent material on the back side of the substrate and removing the layer from a small area to expose the substrate; etching the exposed substrate from the back side to the etch stop layer on the front side. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method for fabricating an X-ray beamsplitter comprising:
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depositing a thin layer of X-ray transparent material on a front surface of a substrate; depositing a thin multiplayer film of periodic alternating layers on the layer of X-ray transparent material which resonantly reflects, and transmits X-rays of wavelength λ
incident at an angle θ
;etching the substrate from a back surface to the layer of X-ray transparent material on the front surface to form a window through the substrate over which the layer of X-ray transparent material and thin multilayer film extent. - View Dependent Claims (17, 18, 19)
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20. A method for fabricating an X-ray beamsplitter, comprising:
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forming thin substantially flat X-ray transparent supporting membrane; forming a thin multilayer film on the membrane which resonantly reflects, and transmits X-rays of wavelength λ
incident at an angle θ and
has a periodicity d given by
space="preserve" listing-type="equation">λ
=2 μ
d sin θwhere θ
is the angle of incidence measured from the surface of the beamsplitter and μ
is a predetermined factor which accounts for refractive effects in the multilayer film.
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21. A resonant cavity for supporting X-ray laser action, comprising:
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a multilayer thin film rear cavity X-ray mirror; an X-ray beamsplitter spaced from and aligned with the rear cavity mirror along a cavity axis, the beamsplitter comprising; a substrate having a window therethrough; a very thin substantially flat X-ray transparent support membrane deposited on the substrate and extending across the window therein; a thin multilayer film deposited on the membrane and over the window in the substrate which resonantly reflects and transmits X-rays of wavelength λ
incident at an angel θ and
has a periodicity d given by
space="preserve" listing-type="equation">λ
=2 μ
d sin θwhere θ
is the angle of incidence measured from the surface of the beamsplitter and λ
is a predetermined factor which accounts for refractive effects in the multilayer film; and
a gain media positioned between the rear cavity X-ray mirror and the X-ray beamsplitter along said axis. - View Dependent Claims (22, 23, 24, 25)
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Specification