Mr. Edward A. Miller Profile

Edward A. Miller

Systems Engineer at Jet Propulsion Lab

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Publications (4)

Proceedings Article | 20 November 2017 Open Access

Multi-mode optical fibers for connecting space-based spectrometers

W. T. Roberts, C. Lindenmisth, S. Bender, E. Miller, E. Motts, M. Ott, F. LaRocca, J. Thomes

Proceedings Volume 10565, 105651A (2017) https://doi.org/10.1117/12.2309137

KEYWORDS: Spectrometers, Optical fibers, Cladding, Astronomical imaging, Laser induced breakdown spectroscopy, Raman spectroscopy, Head, Light scattering, Silica, Plasma

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Laser spectral analysis systems are increasingly being considered for in situ analysis of the atomic and molecular composition of selected rock and soil samples on other planets [1][2][3]. Both Laser Induced Breakdown Spectroscopy (LIBS) and Raman spectroscopy are used to identify the constituents of soil and rock samples in situ. LIBS instruments use a high peak-power laser to ablate a minute area of the surface of a sample. The resulting plasma is observed with an optical head, which collects the emitted light for analysis by one or more spectrometers. By identifying the ion emission lines observed in the plasma, the constituent elements and their abundance can be deduced. In Raman spectroscopy, laser photons incident on the sample surface are scattered and experience a Raman shift, exchanging small amounts of energy with the molecules scattering the light. By observing the spectrum of the scattered light, it is possible to determine the molecular composition of the sample.

For both types of instruments, there are advantages to physically separating the light collecting optics from the spectroscopy optics. The light collection system will often have articulating or rotating elements to facilitate the interrogation of multiple samples with minimum expenditure of energy and motion. As such, the optical head is often placed on a boom or an appendage allowing it to be pointed in different directions or easily positioned in different locations. By contrast, the spectrometry portion of the instrument is often well-served by placing it in a more static location. The detectors often operate more consistently in a thermally-controlled environment. Placing them deep within the spacecraft structure also provides some shielding from ionizing radiation, extending the instrument’s useful life. Finally, the spectrometry portion of the instrument often contains significant mass, such that keeping it off of the moving portion of the platform, allowing that portion to be significantly smaller, less massive and less robust.

Large core multi-mode optical fibers are often used to accommodate the optical connection of the two separated portions of such instrumentation. In some cases, significant throughput efficiency improvement can be realized by judiciously orienting the strands of multi-fiber cable, close-bunching them to accommodate a tight focus of the optical system on the optical side of the connection, and splaying them out linearly along a spectrometer slit on the other end.

For such instrumentation to work effectively in identifying elements and molecules, and especially to produce accurate quantitative results, the spectral throughput of the optical fiber connection must be consistent over varying temperatures, over the range of motion of the optical head (and it’s implied optical cable stresses), and over angle-aperture invariant of the total system. While the first two of these conditions have been demonstrated[4], spectral observations of the latter present a cause for concern, and may have an impact on future design of fiber-connected LIBS and Raman spectroscopy instruments. In short, we have observed that the shape of the spectral efficiency curve of a large multi-mode core optical fiber changes as a function of input angle.

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Proceedings Article | 5 March 2003 Paper

NGST MIRI instrument

Gillian Wright, Fabio Bortoletto, Carl Bruce, Ewine van Dishoeck, Avinash Karnik, Pierre-Olivier Lagage, Melora Larson, Dietrich Lemke, Goran Oloffson, Edward Miller, Thomas Henning, Sam Heys, Tom Ray, J. Rodriguez, Eugene Serabyn, Ian Walters

Proceedings Volume 4850, (2003) https://doi.org/10.1117/12.461607

KEYWORDS: Spectroscopy, Sensors, Imaging spectroscopy, Imaging systems, Thermography, Mid-IR, Calibration, Spectroscopes, Image resolution, Mirrors

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Proceedings Article | 7 October 1996 Paper

The Visual and Infrared Mapping Spectrometer for Cassini

Edward Miller, Gail Klein, David Juergens, Kenneth Mehaffey, Jeffrey Oseas, Ramon Garcia, Anthony Giandomenico, Robert Irigoyen, Roger Hickok, David Rosing, Harold Sobel, Carl Bruce, Enrico Flamini, Romeo DeVidi, Francis Reininger, Michele Dami, Alain Soufflot, Yves Langevin, Gerard Huntzinger

Proceedings Volume 2803, (1996) https://doi.org/10.1117/12.253421

KEYWORDS: Calibration, Electronics, Spectroscopy, Mirrors, Sensors, Staring arrays, Infrared spectroscopy, Space operations, Visible radiation, Infrared imaging

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Proceedings Article | 1 August 1991 Paper

Requirements of a solar diffuser and measurements of some candidate materials

Carmen Guzman, James Palmer, Philip Slater, Carol Bruegge, Edward Miller

Proceedings Volume 1493, (1991) https://doi.org/10.1117/12.46690

KEYWORDS: Reflectivity, Ultraviolet radiation, Diffusers, Polarization, Calibration, Short wave infrared radiation, Sensors, Radiometry, Microwave radiation, Luminescence

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