Kaiser Optical Systems Inc.

Ann Arbor, MI, United States

Kaiser Optical Systems Inc.

Ann Arbor, MI, United States
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A monolithic optical element and system is used for collimating or focusing laser light from or to optical fibers. The optical fiber terminates in a tip that directly abuts against the first surface of the optical element. The optical element may provide a collimation or focusing function depending upon whether the abutting fiber delivers light for collimation or receives focused light from a collimated beam. The optical element may be a standard or modified barrel or drum lens, with the first and second surfaces being convex curved surfaces having the same or different radii of curvature. The end of the optical element to which the fiber abuts may have a diameter to match the inner diameter of a ferrule for positioning the fiber. A pair of the elements may be used for collimation and focusing in a Raman probehead or other optical detection system.


Wiegand P.,Kaiser Optical Systems Inc.
Proceedings of the Annual ISA Analysis Division Symposium | Year: 2016

For gasoline analysis, extractive and non-extractive analyzers are used as process analyzers. While gas chromatographs are considered the industry standard, they require an extractive sample system with a high cost of ownership. Several non-extractive analyzers are in use because they provide rapid in situ monitoring. Raman spectroscopy is an in-process analyzer providing robustness, method transferability, high specificity and low cost of ownership. The sharp Raman spectral features enable highly-specific and quantitative analyses. Because of these features, Raman spectroscopy has been implemented successfully in many petrochemical applications. Since the 1990s, Raman spectroscopic process analyzers have been capable of in-situ fiber-optic based quantitative process analyses. Raman analyzers and probes specifically engineered for the process environment are capable of measurements from cryogenic temperatures to hundreds of degrees and pressures to thousands of psi. Use of a three-point standardization protocol traceable to National Institute of Standards and Technology (NIST) standards, allows transfer of calibrations between instruments, and imparts long-term method robustness. This complete solution has allowed customers to analyze many difficult-to-sample materials, including diatomic species. This paper will focus on the use of hazardous area RamanRXN3™ analyzers for analyzing sulfur species in gasoline. This is a preliminary study and is not being proposed as a substitute for any existing methods at this time. Yet these encouraging results are promising enough to warrant additional work in this area.


Raw data inputs are treated as independent signal sources to reduce computational lag without adversely affecting signal-to-noise ratio (SNR). Applications include spectroscopy, multiple linear regression, mass balance quantitation and the calculation of physical properties. The input-specific averaging has been applied to Raman spectroscopy, where the inputs are averaged spectra from which peak heights or areas are obtained from integration. Alternatively, peak areas or heights can be obtained from unaveraged spectra and are then averaged before use in further calculations as inputs to produce a desired output. The output(s) are linear or nonlinear combinations of the peak heights or areas, coupled with weighting factors which relate the raw inputs to a quantitative output such as concentration of a chemical species. Each specific input can use a different type of averaging. The overall goal may be optimization for best precision, and/or optimization for minimum lag time.


Patent
Kaiser Optical Systems Inc. | Date: 2012-08-01

Raman signal amplification apparatus comprises an ellipsoidal reflector providing a first real focus f1, and second real or virtual focus f2, both foci being situated within a sample volume. When an input laser excitation beam having an initial numerical aperture (NA) is focused onto one of the foci, the beam is reflected by the reflector and refocused onto alternating foci, such that the NA of the reflected optical path progressively increases for higher efficiency collection of Raman emissions from the multiple foci. The ellipsoidal reflector may be a half section providing a single real focus f1, with a flat reflector producing a mirror image of the ellipsoidal reflector, such that f2 is a virtual focus occupying the same point as f1. Alternatively, the ellipsoidal reflector may have a first half section with a first real focus f1 and a second half section with a second real focus f2.


Patent
Kaiser Optical Systems Inc. | Date: 2011-05-27

A compact Raman analysis system combines a near-infrared (NIR) laser source, a 2D array collecting anti-Stokes Raman spectra, and a probe configured to measure complex solid samples, including pharmaceutical tablets and other large-area targets with reduced background fluorescence at relatively low cost. The system collects spectra from an area of 1-mm or greater, preferably 3-12 mm or more, facilitating the collection of statistically useful data from inhomogeneous and laser-sensitive samples, among other applications. Potential pharmaceutical applications include tablet dosage level measurements, as well as online and at-line quality-control (QC) monitoring opportunities. Other applications include tablet identification as a forensic tool to identify counterfeit pharmaceutical products; granulation and blend uniformity for improved formulation via better process understanding,


A monolithic optical element and system is used for collimating or focusing laser light from or to optical fibers. The optical fiber terminates in a tip that directly abuts against the first surface of the optical element. The optical element may provide a collimation or focusing function depending upon whether the abutting fiber delivers light for collimation or receives focused light from a collimated beam. The optical element may be a standard or modified barrel or drum lens, with the first and second surfaces being convex curved surfaces having the same or different radii of curvature. The end of the optical element to which the fiber abuts may have a diameter to match the inner diameter of a ferrule for positioning the fiber. A pair of the elements may be used for collimation and focusing in a Raman probehead or other optical detection system.


Methods and systems for spectrometer dark correction are described which achieve more stable baselines, especially towards the edges where intensity correction magnifies any non-zero results of dark subtraction, and changes in dark current due to changes in temperature of the camera window frame are typically more pronounced. The resulting induced curvature of the baseline makes quantitation difficult in these regions. Use of the invention may provide metrics for the identification of system failure states such as loss of camera vacuum seal, drift in the temperature stabilization, and light leaks. In system aspects of the invention, a processor receives signals from a light detector in the spectrometer and executes software programs to calculate spectral responses, sum or average results, and perform other operations necessary to carry out the disclosed methods. In most preferred embodiments, the light signals received from a sample are used for Raman analysis.


Methods and systems for spectrometer dark correction are described which achieve more stable baselines, especially towards the edges where intensity correction magnifies any non-zero results of dark subtraction, and changes in dark current due to changes in temperature of the camera window frame are typically more pronounced. The resulting induced curvature of the baseline makes quantitation difficult in these regions. Use of the invention may provide metrics for the identification of system failure states such as loss of camera vacuum seal, drift in the temperature stabilization, and light leaks. In system aspects of the invention, a processor receives signals from a light detector in the spectrometer and executes software programs to calculate spectral responses, sum or average results, and perform other operations necessary to carry out the disclosed methods. In most preferred embodiments, the light signals received from a sample are used for Raman analysis.


Patent
Kaiser Optical Systems Inc. | Date: 2013-05-28

Methods and apparatus facilitate dynamic range balancing for multi-component peaks of widely varying magnitude in an optical spectrometer. In a specific embodiment, filters attenuate the CH stretch region to produce a better fit of a multi-component hydrocarbon Raman spectrum to the dynamic range of a CCD detector. The filter may be translated into and out of the collimated collection beam to achieve a varying degree of attenuation. In certain applications, the filter is insertable into a collimated collection beam within a fiber-optic probe head to collect Raman spectra. The invention may include optical elements to create the collimated collection beam if not already present or not suitable for insertion of the filter. A second filter, an opaque or neutral density filter, may be insertable into the collimated collection beam to attenuate a broad spectral response within and outside the spectral range.


A material which is generally transparent in the visible region of the spectrum but reflective at laser wavelengths reduces undesirable, substrate-induced Raman and fluorescence scattering. A substrate provides a surface for supporting the sample, with the material being disposed between the surface of the substrate and the sample. The material is substantially transparent in the visible region of the spectrum but reflective at the laser wavelength, thereby minimizing unwanted Raman or fluorescence scattering that would be produced by the substrate if the material were not present. The substrate will typically be a glass microscope slide or multi-cell well plate. The optical filter material is preferably a multilayer dielectric filter acting as a hot mirror that reflects near-infrared energy. An advantage of visible transmission is that it allows back illumination from behind/underneath the slide or well plate, thereby being visible to a microscopes eyepiece or video camera. Methods and article are also disclosed.

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