Multi-etalon VISAR interferometer having an interferometer frame of high stiffness with a linear elongated slide bar
First Claim
1. An improved multi-etalon VISAR interferometer, comprising traditional multi-etalon VISAR interferometer components, said traditional multi-etalon VISAR interferometer components comprisinga first beamsplitter means,a second beamsplitter means,two separate interferometer light paths,multiple precision glass plates, said glass plates being referred to as delay etalons, andfixed optical components and movable optical components;
- said first beamsplitter means acting to split an incident light beam to travel through said two separate interferometer light paths before being recombined by said second beamsplitter means to form interference fringes, said two separate interferometer light paths being referred to respectively as the reference leg and the delay leg, with the lengths of said two separate interferometer light paths being referred to respectively as the reference leg length and the delay leg length, said delay leg length being longer than said reference leg length for introducing a delay in the portion of said incident light beam which traverses said delay leg before recombination;
said delay leg being designed to accept various combinations of said delay etalons disposed in said delay leg of said VISAR interferometer, said VISAR interferometer having the characteristic that best fringe resolution can be obtained only at a precise optimum delay leg length as compared to said reference leg length, said optimum delay leg length being dependent on the thicknesses and indices of refraction of those said delay etalons which comprise the particular combination of said delay etalons which are disposed in said delay leg;
said movable optical components being those which are designed to move with respect to said fixed optical components in order to achieve said optimum delay leg length for any said particular combination of said delay etalons which are disposed in said delay leg;
wherein the improvement in said improved multi-etalon VISAR interferometer comprises a fringe alignment preservation means comprisinga. an interferometer frame of high stiffness, to which said fixed optical components of said VISAR interferometer are securely attached;
b. a linear elongated slide bar to which said movable optical components of said VISAR interferometer are securely attached;
c. a linear elongated slide bar track means integral with said interferometer frame, which guides said slide bar in its longitudinal direction for allowing changes to be made in said delay leg length of said VISAR interferometer, said slide bar and said slide bar track means together serving to preserve, to a high degree of precision, the angular orientation of said movable optical components when said slide bar is longitudinally moved in said slide bar track means to change said delay leg length; and
d. attachment means for attaching said slide bar at various positions in said slide bar track means for allowing adjustment of said delay leg length,said interferometer frame, said slide bar, said slide bar track means, and said attachment means all being of such stiffness, design, and precision as to preserve said VISAR interferometer'"'"'s fringe alignment to the extent that visible fringes are still present after said VISAR interferometer'"'"'s delay leg length is changed from one said optimum delay leg length, corresponding to a certain combination of said delay etalons, to a new said optimum delay leg length, corresponding to a new combination of said delay etalons.
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Accused Products
Abstract
A multi-etalon VISAR interferometer with variable velocity-per-fringe constant, capable of measuring the velocity of a diffusely-reflecting surface, having design innovations which preserve the fringe alignment of the interferometer even when its velocity-per-fringe constant is changed or when it is exposed to environmental stress such as substantial temperature changes or being moved from one location to another. The interferometer stability is enhanced by using a very stiff interferometer frame, to which the alignment-sensitive components of the interferometer are attached. The movable interferometer components are attached to a relatively long slide bar which can be attached to the interferometer frame at various locations in a slide bar track in the interferometer frame. Delay leg spacers allow the slide bar, with its movable interferometer components, to be positioned easily and accurately when changing the velocity-per-fringe constant.
10 Citations
18 Claims
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1. An improved multi-etalon VISAR interferometer, comprising traditional multi-etalon VISAR interferometer components, said traditional multi-etalon VISAR interferometer components comprising
a first beamsplitter means, a second beamsplitter means, two separate interferometer light paths, multiple precision glass plates, said glass plates being referred to as delay etalons, and fixed optical components and movable optical components; -
said first beamsplitter means acting to split an incident light beam to travel through said two separate interferometer light paths before being recombined by said second beamsplitter means to form interference fringes, said two separate interferometer light paths being referred to respectively as the reference leg and the delay leg, with the lengths of said two separate interferometer light paths being referred to respectively as the reference leg length and the delay leg length, said delay leg length being longer than said reference leg length for introducing a delay in the portion of said incident light beam which traverses said delay leg before recombination;
said delay leg being designed to accept various combinations of said delay etalons disposed in said delay leg of said VISAR interferometer, said VISAR interferometer having the characteristic that best fringe resolution can be obtained only at a precise optimum delay leg length as compared to said reference leg length, said optimum delay leg length being dependent on the thicknesses and indices of refraction of those said delay etalons which comprise the particular combination of said delay etalons which are disposed in said delay leg;
said movable optical components being those which are designed to move with respect to said fixed optical components in order to achieve said optimum delay leg length for any said particular combination of said delay etalons which are disposed in said delay leg;
wherein the improvement in said improved multi-etalon VISAR interferometer comprises a fringe alignment preservation means comprisinga. an interferometer frame of high stiffness, to which said fixed optical components of said VISAR interferometer are securely attached; b. a linear elongated slide bar to which said movable optical components of said VISAR interferometer are securely attached; c. a linear elongated slide bar track means integral with said interferometer frame, which guides said slide bar in its longitudinal direction for allowing changes to be made in said delay leg length of said VISAR interferometer, said slide bar and said slide bar track means together serving to preserve, to a high degree of precision, the angular orientation of said movable optical components when said slide bar is longitudinally moved in said slide bar track means to change said delay leg length; and d. attachment means for attaching said slide bar at various positions in said slide bar track means for allowing adjustment of said delay leg length, said interferometer frame, said slide bar, said slide bar track means, and said attachment means all being of such stiffness, design, and precision as to preserve said VISAR interferometer'"'"'s fringe alignment to the extent that visible fringes are still present after said VISAR interferometer'"'"'s delay leg length is changed from one said optimum delay leg length, corresponding to a certain combination of said delay etalons, to a new said optimum delay leg length, corresponding to a new combination of said delay etalons. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A new multi-etalon VISAR interferometer comprising traditional multi-etalon VISAR interferometer components, said traditional multi-etalon VISAR interferometer components comprising
a first beamsplitter means, a second beamsplitter means, two separate interferometer light paths, multiple precision glass plates, said glass plates being referred to as delay etalons, and fixed optical components and movable optical components; -
said first beamsplitter means acting to split an incident light beam to travel through said two separate interferometer light paths before being recombined by said second beamsplitter means to form interference fringes, said two separate interferometer light paths being referred to respectively as the reference leg and the delay leg, with the lengths of said two separate interferometer light paths being referred to respectively as the reference leg length and the delay leg length, said delay leg length being longer than said reference leg length for introducing a delay in the portion of said incident light beam which traverses said delay leg before recombination;
said delay leg being designed to accept various combinations of said delay etalons disposed in said delay leg of said VISAR interferometer, said VISAR interferometer having the characteristic that best fringe resolution can be obtained only at a precise optimum delay leg length as compared to said reference leg length, said optimum delay leg length being dependent on the thicknesses and indices of refraction of those said delay etalons which comprise the particular combination of said delay etalons which are disposed in said delay leg;
said movable optical components being those which are designed to move with respect to said fixed optical components in order to achieve various values of said delay leg length for allowing said optimum delay leg length to be achieved for any said particular combination of said delay etalons which are disposed in said delay leg;
said new VISAR interferometer also comprising a fringe alignment preservation means which makes the fringe alignment of said VISAR interferometer much more stable than in previous multi-etalon VISARs, said fringe alignment preservation means comprisinga. an interferometer frame of high stiffness, to which said fixed optical components of said VISAR interferometer are securely attached; b. a linear elongated slide bar to which said movable optical components of said VISAR interferometer are securely attached; c. a linear elongated slide bar track means integral with said interferometer frame, which guides said slide bar in its longitudinal direction for allowing changes to be made in said delay leg length of said VISAR interferometer, said slide bar and said slide bar track means together serving to preserve, to a high degree of precision, the angular orientation of said movable optical components when said slide bar is longitudinally moved in said slide bar track means to change said delay leg length; and d. attachment means for attaching said slide bar at various positions in said slide bar track means, thus allowing adjustment of said delay leg length, said interferometer frame, said slide bar, said slide bar track means, and said attachment means all being of such stiffness, design, precision, and thermal properties as to preserve said interferometer'"'"'s fringe visibility during normal usage. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification