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Optical Engineering

Noise measurements of a phase fluorometric instrument
Author(s): Raja Holavanahalli; Gary M. Carter; Shabbir B. Bambot; Vadde Venkatesh; Vivek Srinivas
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Paper Abstract

We present noise measurements of a phase fluorometric oxygen sensor that sets the limits of accuracy for this instrument. We analyze the phase sensitive detection measurement system with the signal ‘‘shot’’ noise being the only significant contribution to the system noise. Based on the modulated optical power received by the photomultiplier, the analysis predicts a noise spectral power density that was within 3 dB of the measured power spectral noise density. Our results demonstrate that at a received optical power of 20 fW the noise level was low enough to permit the detection of a change oxygen concentration of 1% at the sensor. We also present noise measurements of a new low-cost version of this instrument that uses a photodiode instead of a photomultiplier. These measurements show that the noise for this instrument was limited by noise generated in the preamplifier following the photodiode.

Paper Details

Date Published: 1 February 1996
PDF: 5 pages
Opt. Eng. 35(2) doi: 10.1117/1.601024
Published in: Optical Engineering Volume 35, Issue 2
Show Author Affiliations
Raja Holavanahalli, Univ. of Maryland/Baltimore (United States)
Gary M. Carter, Univ. of Maryland/Baltimore (United States)
Shabbir B. Bambot, Univ. of Maryland/Baltimore County (United States)
Vadde Venkatesh, Indian Institute of Science (India)
Vivek Srinivas, Indian Institute of Science Bangalore (India)

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