Applied Optical Spectroscopy

Optical spectroscopy (a highly accountable reference on applied spectroscopy [1]), has for a long time been a basic tool for materials research and inspection. Optoelectronic innovations such as light sources, detectors, displays, etc. have their foundations in optical spectroscopy. There are different ways to specify optical spectroscopies such as transmission, reflection, fluorescence, spectro-scopies. Quite often the spectral region defines the name of the spectroscopy such as UV, visible and NIR spectroscopy. The wavelength of electromagnetic radiation has a great role in the sense that it is sensitive to the basic units of the medium, namely electrons, atoms and molecules that experience the electromagnetic interaction. Nowadays, a rough way to separate different optical spectroscopies into two main classes is to speak of linear- and nonlinear optical spectroscopies. Well established protocols for the use of spectral devices, involving measurements in the field of linear optical spectroscopy, have been furnished, and spectrophotometers can be found in well-equipped laboratories, e.g., for medical and industrial inspection of samples, respectively. The number of industrial products or clinical samples that are inspected by spectral devices is very wide. One basic property is the colour of the sample.

Thanks to the cheaper optoelectronics, robust measurement systems have been built for routine inspection of solid, liquid, and gaseous samples. A variety of commercial miniature spectrometers with software for data processing and displaying are on the markets, and one can easily find up-to-date information of commercial spectrophotometers in the Internet. These miniature spectrophotometers are currently developed so that they offer relatively high resolution of wavelength and concentration of species for various types of real time measurements. Some of these spectrometers involve a fiber optic probe, for instance, for the detection of fluorescence from a product or monitoring fluorescent traces in turbid liquid media. The applications of optical spectroscopy are not limited to medical or industrial purposes only. Security of human beings is becoming more important with globalization. Therefore, spectrometers that can record lethal media such as bacteria and explosives have already been developed and are on their way to general use both in civil and military environments. In forensic studies spectrometers are already everyday life. Future trend in realizing miniature spectrometers for process industry relies on micro electro mechanical systems (MEMS) produced by micro-lithography. Low price, durability and resistance against thermal and mechanical disturbances of such micro-spectrometers will enhance their application in hostile environments of process industry.