A light intensity function suitable for multimode fiber-optic sensors

He, Gang; Cuomo, Frank W.

doi:10.1109/50.76670

Cited by 37 publications

(27 citation statements)

References 10 publications

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“…Simulations are carried out applying the model introduced by He and Cuomo [1] in which the fluorescent sample is excited via a Lambertian light source whose light is coupled into a multimode fibre. The collection efficiencies are calculated for the four detection configurations illustrated in figure 1a.…”

Section: Methodsmentioning

confidence: 99%

Fluorescence excitation emission matrix spectroscopy of strongly absorbing samples using fibre-optic probes

Munzke

Saunders

Omrani

et al. 2013

2013 Conference on Lasers &Amp; Electro-Optics Europe &Amp; International Quantum Electronics Conference CLEO EUROPE/IQEC

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IntroductionFibre-optic probes play an increasing role in the investigation of a variety of condensed media, for example in the food industry, in medicine and in the oil industry. Using single fibres or fibre bundles fluorescence can be excited and collected even if the samples are strongly absorbing such as process liquids and lubricants. In combination with fluorescence excitation-emission matrix (EEM) spectroscopy two dimensional data arrays are generated that contain qualitative and quantitative information about the composition of the sample. In this report we explicitly consider the effects of primary and secondary absorption in fluorescence EEM spectroscopy, and identify the optimal detection configuration of the fibre-optic fluorescence probe facilitating the largest possible dynamic concentration range. Theoretical results were validated with in situ measurements of strongly absorbing machinery fluids.

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Section: Methodsmentioning

confidence: 99%

Fluorescence excitation emission matrix spectroscopy of strongly absorbing samples using fibre-optic probes

Munzke

Saunders

Omrani

et al. 2013

2013 Conference on Lasers &Amp; Electro-Optics Europe &Amp; International Quantum Electronics Conference CLEO EUROPE/IQEC

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“…He and Cuomo [5] derived a formula for the optical power coupling factor by determining the light reflected from a deflected membrane in an optical lever microphone when multimode optical fibers are used to transmit and receive light. They determined the optical power coupled by using a ring approximation as shovm in Figure 5.…”

Section: Figure 4 Methods Of Imagesmentioning

confidence: 99%

“…Previous optical microphone noise studies (He and Cuomo 1991 [5], 1992 [9]) acknowledge the presence of light source intensity noise, but only consider the photodiode shot noise in theoretical models. While photodiode shot noise is the dominant noise source generated in the electrical domain, the optical noise power incident on the active area of the photodiode can also be significant, and should be included in an overall model for the optical microphone MDS.…”

Section: Minimum Detectable Signalmentioning

confidence: 99%

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Design and Characterization of MEMS Optical Microphone for Aeroacoustic Measurement

Kadirvel

Taylor

Horowitz

et al. 2004

42nd AIAA Aerospace Sciences Meeting and Exhibit

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Public Reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completmg and reviewing the collection of information. Send comment regarding this burden estimates or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and The views, opinions and/or findings contained in this report are those of the author(s) and should not be construed as an official Department of the Army position, policy or decision, unless so designated by other documentation. This paper presents the design and characterization of an intensity modulated optical lever microphone. Optical microphones (OM) have an inherent immunity to environments hostile to electronics due to the spatial separation of the electronics and the acoustic field under test. Theoretical equations for the sensitivity, minimum detectable signal, and frequency response are presented. Physical phenomena responsible for limiting the microphone minimum detectable signal (MDS) are identified, and a model is developed for use with a laser diode as the light source. The characterization of the microphone indicates an overall sensitivity of 0.5 mV/Pa, a linear response up to 132dB ref. 20 uPa, and an overall noise floor of 70dB measured at 1kHz over a 1Hz bin. SUBJECT TERMS MEMS AbstractThis paper presents the design and characterization of an intensity modulated optical lever microphone. Optical microphones (CM) have an inherent immunity to environments hostile to electronics due to the spatial separation of the electronics and the acoustic field under test.Theoretical equations for the sensitivity, minimum detectable signal, and frequency response are presented. Physical phenomena responsible for limiting the microphone minimum detectable signal (MDS) are identified, and a model is developed for use with a laser diode as the light source.The characterization of the microphone indicates an overall sensitivity of 0.5 mV/Pa, a linear response up to 132dB ref. 20 uPa, and an overall noise floor of 70dB measured at IkHz over a IHz bin.

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“…The experimental setup is presently based on either a lamp or a laser (as in this paper) as a light source but will eventually involve a battery of fibercoupled LEDs. We are therefore using a lightemission model that is believed to represent the emission from a Lambertian light source such as an LED with a high degree of accuracy [22].…”

Section: Introductionmentioning

confidence: 99%

Modeling of fiber-optic fluorescence probes for strongly absorbing samples

et al. 2012

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The dynamic range of fiber-optic fluorescent probes such as single fibers and fiber bundles is calculated for strongly absorbing samples, such as process liquids, foodstuffs, and lubricants. The model assumes an excitation beam profile based on a Lambertian light source and uses analytical forms of the collection efficiency, followed by an Abel transformation and numerical integration. It is found that the effect of primary absorption of the excitation light and secondary absorption of the fluorescence is profound. For fiber bundles and bifurcated fiber probes, the upper accessible concentration limit is roughly given by the absorption length of the primary and secondary absorption. Fluorescence detectors that are placed at right angles to the excitation beam axis or collinear to the beam axis are equally strongly affected by secondary absorption. A probe in which the same fiber is used for excitation and for collection of the fluorescence emerges as the fiber probe with the largest accessible concentration range.

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A light intensity function suitable for multimode fiber-optic sensors

Cited by 37 publications

References 10 publications

Fluorescence excitation emission matrix spectroscopy of strongly absorbing samples using fibre-optic probes

Fluorescence excitation emission matrix spectroscopy of strongly absorbing samples using fibre-optic probes

Design and Characterization of MEMS Optical Microphone for Aeroacoustic Measurement

Modeling of fiber-optic fluorescence probes for strongly absorbing samples

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