Deformometer for determining deformation of an optical cavity optic
Inventors
Ahmed, Zeeshan • 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-10816325-B2
Publication Date
2020-10-27
Expiration Date
2039-07-24
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
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 disclosed is a deformometer designed for determining deformation of an optical cavity optic disposed on an optical cavity. The deformometer includes an optical cavity with a cavity body, an entry optical cavity optic disposed at the entry end of the cavity body, and an exit optical cavity optic disposed at the exit end, where the entry optical cavity optic is in optical communication and optically opposing the exit optical cavity optic. A first laser and a second laser provide first and second lights, respectively, which are combined to produce a combined light communicated to the entry optical cavity optic. The optical cavity produces filtered combined light from the combined light, which is split and measured by light detectors to produce cavity signals from which deformation of the optical cavity optics is determined.
The deformometer further includes optical combiners, beam splitters, imaging components, optical frequency comb sources, and light detectors arranged to receive, combine, split, and detect the multiple light signals. The deformation of the optical cavity optics is determined by analyzing the filtered light and the signals produced by the detectors, providing a measurement of deformation due to forces such as gas pressure on the cavity optics. The invention also discloses processes for determining deformation by combining lights, transmitting combined light through the cavity, producing filtered combined light, splitting this filtered light, and analyzing the resulting signals to determine deformation.
Claims Coverage
The patent contains multiple independent claims relating to a deformometer device for determining deformation of an optical cavity optic. The claims cover inventive features involving the optical cavity structure, laser light sources, optical combiners and splitters, light detectors, and methods for determining deformation.
Deformometer comprising an optical cavity with entry and exit optics and combined laser lights
A deformometer including an optical cavity with a cavity body, an entry optical cavity optic, an exit optical cavity optic optically opposing the entry optic, first and second lasers providing first and second light respectively, a first optical combiner combining these lights into a combined light, a second optical combiner splitting filtered combined light into first and second filtered light, first and second light detectors producing cavity signals from the filtered light, and an optical frequency comb source producing optical frequency combs; wherein deformation of the entry and exit optical cavity optics is determined from these signals.
Inclusion of probe light and reference light detectors
The deformometer further includes a probe light detector in optical communication with the first laser producing a probe signal, and first and second reference light detectors receiving light from the lasers and optical frequency combs and producing reference signals.
Optical arrangement including beam splitter and imager for filtered light
The beam splitter communicates a portion of the second filtered light to an imager which produces an image signal from this light.
Modulation of laser lights prior to combining
The deformometer has an electrooptic modulator modulating first laser light with an oscillator signal interposed between the first laser and first optical combiner, and an amplitude optical modulator modulating second laser light interposed between the second laser and first optical combiner.
Extension to a second optical cavity with additional lasers and combiners
The deformometer comprises a second optical cavity with its own entry and exit optics, third and fourth lasers providing third and fourth light, third and fourth optical combiners combining and splitting light, third and sixth light detectors, and a second imager; producing cavity signals from which deformation of the second optical cavity optics is determined, along with probe light detectors and reference light detectors for these additional lasers.
Process for determining deformation using combined lights, optical cavity transmission, splitting filtered light and signal detection
A process involving combining first and second light, communicating combined light to the entry optical cavity optic, receiving combined light by the exit optical cavity optic, producing filtered combined light, splitting filtered combined light into first and second filtered light, detecting these to produce cavity signals, producing optical frequency combs and reference signals, and determining deformation from the cavity signals.
The independent claims cover a deformometer system with an optical cavity using combined multiple laser lights, optical combiners and splitters, light detectors producing cavity signals, and optical frequency combs to precisely determine deformation of optical cavity optics. The invention extends to modulation of laser lights, imaging filtered light, additional optical cavities, and a process of analyzing combined and filtered light signals to measure deformation accurately.
Stated Advantages
The deformometer overcomes technical deficiencies of conventional Fabry-Perot refractometers or fixed-length optical cavities, whose measurement accuracy is limited by deformations of optical elements due to gas injection.
It provides a potential primary standard for pressure measurement from 0.1 mPa to 3.6 MPa, enabling primary pressure metrology and self-calibration of pressure transfer standards and deformation effects.
The deformometer allows measurement of refractive index and gas dispersion while accounting for deformation, avoiding assumptions or calculations about material properties of the optical cavity.
It eliminates the need for calibration of Fabry-Perot refractometers and fixed-length optical cavities by removing uncertainty sources from deformation during gas injection.
Documented Applications
Primary pressure metrology and potential realization of the pascal as a quantum-based vacuum metrology standard.
Self-calibration of pressure transfer standards and self-calibration of deformation effects due to external forces.
Measurement of refractive index and dispersion of gases, including known gases such as helium and unknown gases, via optical cavity interrogation.
Application as a primary standard for pressure at a broad range of pressures from low vacuum into the megapascal range.
Interested in licensing this patent?