Multi Fiber Imaging Spectrometer0 pages

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Multiple Fiber

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Imaging

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Spectrometer

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MULTIPLE FIBER IMAGING

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McPherson, Inc. has developed an Ultraviolet, Visible

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and Near Infrared Spectrometer System optimized for

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monitoring fiber coupled telescopes. The 350-mm focal

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length high resolution, research grade spectrometer

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delivers 0.1-mm scale images near axis and < 0.1 -nm

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spectral resolution. The spectrometer includes a reflec-

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tive fiber-coupling accessory to aperture match fast

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fibers to spectrometer optics most effectively. Combined

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with fast-gated detection system wide range spectra can

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be collected to monitor or plot over time the characteris-

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tic of transient phenomena.

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For experiments involving remote events or hostile

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environments use of a telescope to spatially select and

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collect signal is advantageous. An imaging spectrometer

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can allow more data to be collected since multiple fibers

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can be introduced and dispersed simultaneously. For

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example, the impact zone of a high-energy projectile

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often produces a light emission by superheated plasma

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or other detonation. Due to the impact, the immediate

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area is debris filled and would damage sensitive optical

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elements. Use of telescopes allows collecting signal

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from specific areas in the impact zone and analyzing the

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wavelength emission features. Use of multiple tele-

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scopes allows mapping changing spectral characteris-

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tics of the impact area from ground zero to the periphery.

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McPherson builds high quality reflective telescopes for

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this work. Use in the ultraviolet or over broad wavelength

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ranges is facilitated by these devices. They function free

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of chromatic aberration that would otherwise change

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focus and throughput with wavelength.

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Standard versions exist in 50-mm and

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125-mm clear apertures. These are

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parabolic systems optimally condensing

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the collected field to small core diameter

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fibers for transfer to the spectrometer

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entrance slit. Use of these tools allows

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spectroscopy and imaging experiments

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with varying photon energies on multiple

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targets on the nanosecond time scale.

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125-mm clear aperture optical receiver/telescope.

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Still photos from a high-speed image sequence (one millisecond

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between each frame) of an impact by a copper sphere traveling at 4.5

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km/sec into porous pumice. A bright "flash" is a high temperature

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plume resembling a Roman candle that shoots out of the hole created as

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the projectile penetrates into the target. The éjecta curtain resembles a

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funnel. These images courtesy of the NASA Deep Impact web site and Dr.

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P. Schultz, Professor of Geophysics with Brown University.

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The spectrometer system with telescope input optics allows viewing the

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impact zone from a safe distance.

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MCP@mcphersoninc.com, Tel 978-256-4512, Fax 978-250-8625, McPherson 7A Stuart Road Chelmsford MA 01824 USA

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