Professionals in the water and sensing industries, analytical chemists, researchers and undergraduate and graduate students interested in learning new spectroscopic and sensing techniques.
Please bring a laptop computer.
Side illumination of an optical fiber is a new technique that is being used to probe multiple sensing points and samples along the fiber. This new technique is completely different from the regular way optical fibers are illuminated, the so-called axial illumination, uses a single detection system and is low cost. In axial illumination, the fiber’s end face is illuminated whereas in side illumination, its cylindrical surface is illuminated instead.
With this new technique, a considerable amount of light is coupled into the fiber while providing several unexpected advantages and benefits among them:
1. Low cost: multiple sensing points can be illuminated using inexpensive LEDs, a simple switch-ing technique and a single detection system.
2. High spatial resolution or high density of sensing points: the dimension of the light source dic-tates the number of sensing points along the fiber length and its spatial resolution. For instance, a 5 mm, or better, spatial resolution can be obtained with LEDs that have the same diameter. With the introduction of LEDs that are only 1 micron in diameter, it is possible to improve this resolution 500 fold.
3. Multi fold redundancy: its high spatial resolution also results in a multi fold redundancy making this type of device specially suitable for hostile environments.
4. High sensitivity and high dynamic range: by adjusting the intensity of each light source, or combining the multiple sources to act as a single one, it is possible to obtain an extremely high signal which results in high sensitivity.
5. High signal to noise ratio: compared to axial illumination, the signal to noise ratio is much higher in view of the large amount of probing, or excitation, light that is incident over the detector. In view of these benefits and advantages, this technique has been claimed to be, by others, both as a paradigm shift and as revolutionary way of performing measurements with optical fibers.
In addition, recent publications have also claimed precedence of this technique despite work published much earlier in the late 80’s and early 90’s. During this course, we will:
1. Review the pioneering work, in the late 80’s and early 90’s, done with this type of con-figuration.
2. Review the follow up work done between years 2000 and 2005 including a patent that proposed a new unexpected configuration of the side illuminated fiber.
3. Review the latest literature that started to be published worldwide in 2007 including a patent which further expanded the applicability of this technique.
4. Perform simple demonstrations of this concept.
5. Perform simple colorimetric experiments with a device that uses a side illuminated optical fiber. In the process the audience will learn how this technique works and will gain an understanding of its advantages, benefits and capabilities.
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