Photonic article, process for making and using same
Inventors
Hendricks, Jay H. • Strouse, Gregory F. • Ricker, Jacob E. • Olson, Douglas A. • Scace, Gregory E. • Stone, Jack A. • Egan, Patrick F.
Assignees
National Institute of Standards and Technology NIST • United States Department of Commerce
Publication Number
US-9719878-B2
Publication Date
2017-08-01
Expiration Date
2035-03-20
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Abstract
An article to determine a sample condition includes a substrate; a reference optical cavity disposed on the substrate and comprising a reference cavity, the reference optical cavity being configured to support a reference optical resonance and to maintain an axial length of the reference cavity; and a sample optical cavity disposed on the substrate and comprising a sample cavity, the sample optical cavity being configured to support a sample optical resonance and to maintain an axial length of the sample cavity.
Core Innovation
The invention relates to an article comprising a substrate with a reference optical cavity and a sample optical cavity disposed on the substrate. Each cavity supports its respective optical resonance and maintains an axial length of the cavity. The reference optical cavity includes a reference cavity interposed between a first and a second reference cavity mirror, while the sample optical cavity includes a sample cavity interposed between a first and a second sample cavity mirror.
The article can be constructed to have cavities that are either fixed in length or selectively variable in length via components such as variable length members interposed between two substrates with mirrors disposed on opposing substrates. The cavities are configured to receive gases such as a reference gas or a sample gas. Optical resonances in the cavities are used to measure changes that correspond to sample conditions such as pressure, temperature, or refractive index.
The invention addresses the need for a highly sensitive, temporally stable, and responsive photonic article capable of determining sample conditions like pressure, temperature, or refractive index in gases. Traditional methods for determining such conditions may lack the accuracy, sensitivity, or stability offered by photonic cavity-based techniques. The article provides a robust, sensitive, and fast optical-based determination and can also serve as an internal reference standard or be used to determine density.
Claims Coverage
The patent includes three independent claims covering an article with fixed cavities, an article with variable cavity lengths, and processes for determining a sample condition using resonant optical cavities.
An article with fixed reference and sample optical cavities maintaining axial length on a substrate
An article comprising a substrate; a reference optical cavity disposed on the substrate comprising a reference cavity supporting a reference optical resonance and maintaining an axial length; and a sample optical cavity disposed on the substrate comprising a sample cavity supporting a sample optical resonance and maintaining an axial length.
An article with variable length optical cavities formed between opposing substrates and mirrors
An article comprising a first substrate and a second substrate spaced apart and opposingly disposed; a plurality of first mirrors on the first substrate; a plurality of second mirrors on the second substrate; a variable length member interposed between the first and second substrates with an internal hollow portion; a reference optical cavity with a first pair of opposing mirrors interposing the reference cavity including the internal hollow portion; and a sample optical cavity with a second pair of opposing mirrors, different from the first pair, interposing the sample cavity, all configured to support respective optical resonances and to receive respective gases.
Processes for determining a sample condition using reference and sample optical cavities
Processes comprising introducing reference light to a reference cavity and sample light to a sample cavity; adjusting and locking the lights to their respective cavities; transmitting the lights; combining the reference and sample lights; detecting a beat frequency based on the combined lights; and determining a sample condition such as pressure, temperature, or refractive index based on the beat frequency.
The independent claims cover articles with fixed and variable length optical cavities supporting optical resonances and processes using these cavities to determine sample conditions by detecting beat frequencies between reference and sample lights.
Stated Advantages
Provides a highly sensitive, temporally stable, and responsive optical-based determination of sample conditions like pressure, temperature, or refractive index.
Acts as a robust internal reference standard for various gas measurements.
Can determine density and be constructed as a monolithic structure or interconnected pieces.
Allows selective adjustment of cavity lengths and maintains functionality over arbitrary size dimensions.
Achieves high precision and accuracy in measurements comparable to national primary pressure standards.
Documented Applications
Determination of pressure, temperature, or refractive index of sample gases, including purity assessments and detection of analyte gases in gas compositions.
Use in systems to determine absolute pressure of analyte gases through comparison with a reference gas and measuring pressure differences using null detectors.
Use as a barometric sensor to provide absolute pressure measurements of gases based on beat frequencies from optical resonances.
Detection and quantification of analyte gases in compositions by determining refractive index changes and relating them to the composition's gas components.
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