Deformometer for determining deformation of an optical cavity optic
Inventors
Douglass, Kevin O. • Eckel, Stephen P. • Egan, Patrick F. • Hendricks, Jay H. • Stone, JR., Jack A.
Assignees
United States Department of Commerce
Publication Number
US-10942089-B2
Publication Date
2021-03-09
Expiration Date
2039-07-24
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Abstract
A deformometer includes: a cavity body; entry and exit optical cavity optics, such that the optical cavity produces filtered combined light from combined light; a first laser that provides first light; a second laser that provides second light; an optical combiner that: receives the first light; receives the second light; combines the first light and the second light; produces combined light from the first light and the second light; and communicates the combined light to the entry optical cavity optic; a beam splitter that: receives the filtered combined light; splits the filtered combined light; a first light detector in optical communication with the beam splitter and that: receives the first filtered light from the beam splitter; and produces a first cavity signal from the first filtered light; and a second light detector that: receives the second filtered light; and produces a second cavity signal from the second filtered light.
Core Innovation
The invention is a deformometer designed to determine deformation of an optical cavity optic disposed on an optical cavity or optical cell. The deformometer includes an optical cavity or cell with a cavity body and optical cavity optics disposed at entry and exit ends of the cavity body, arranged such that combined light is received and transmitted through the cavity, producing filtered or shifted combined light. Two or more lasers provide distinct light beams, which are combined and communicated to the entry optical cavity optic, and light detectors detect filtered light from the exit optical cavity optic to produce cavity signals from which deformation is determined.
The method involves combining first and second light sources into combined light transmitted through the optical cavity. The cavity produces filtered combined light, which is split into multiple filtered light components detected by light detectors. By analyzing signals from these detectors, the deformation of the optical cavity optics is determined. This technique allows measurement of deformation caused by forces such as gas pressure acting on the optical elements, using differences in refractive index or light frequencies at different wavelengths or gases.
Claims Coverage
The claims include one independent claim that discloses the deformometer apparatus and one independent claim describing the process for determining deformation using the deformometer.
Deformometer apparatus for determining deformation of an optical cell optic horizontally arranged
An apparatus comprising an optical cell with a cell body, an entry optical cell optic and an exit optical cell optic positioned at opposite ends receiving and transmitting combined light which produces shifted combined light; two lasers providing first and second light combined and communicated into the optical cell; optical elements including propagation coupler, beam splitters, optical combiner, light detectors, and phase detectors arranged to receive, split, detect, and process filtered and shifted light signals to produce cavity and phase signals from which deformation of the optical cell optics is determined.
Process for determining deformation of an optical cell optic
A method comprising combining first and second light to produce combined light, receiving combined light at an entry optical cell optic at the entry end of a deformometer cell body, transmitting combined light to an exit optical cell optic at the exit end, producing filtered combined light, producing first and second filtered light components therefrom, and analyzing those components to determine deformation of the entry and exit optical cell optics.
The claims cover an optical deformometer apparatus that uses combined laser lights, an optical cell with entry and exit optics, and detectors configured to measure filtered and shifted light to determine deformation, as well as a method for performing deformation measurement using such apparatus.
Stated Advantages
Eliminates calibration of Fabry-Perot refractometers and fixed-length optical cavities as pressure standards by removing a source of uncertainty due to deformation of optical elements when gas is injected.
Provides a potential primary standard for pressure measurement over a wide range from 0.1 mPa to 3.6 MPa.
Enables in-situ measurement of deformation without relying on assumptions about material properties by using multiple wavelengths or gas species to separate gas dispersion from cavity deformation.
Facilitates self-calibration of pressure transfer standards and deformation effects due to external forces.
Documented Applications
Primary pressure metrology, providing primary or functionally-primary standards for pressure measurement using optical cavities and refractometry techniques.
Self-calibration of pressure transfer standards.
Self-calibration of deformation effects caused by external forces acting on optical cavity optics.
Measurement of refractive index and dispersion of gases, including unknown gases, once deformation parameters are determined.
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