Important IR component technologies

This section is focused primarily on source and detector technologies. For some applications the source or the detector actually defines the entire measurement technology, for example tunable lasers (source) and array spectrographs (detector). There are other important technologies to consider, especially in the area of data acquisition, control, computer, and commuiucation technologies. These are rapidly changing areas, and if viewed genericaUy, service all forms of instrumentation. Where practical, compaiues tend to use standard platforms, but for certain applications, where performance is critical, there is still a case for proprietary solutions. 

Beyond perfonnance optimization, issues relative to packaging and the need for compliance with certain safety and electronics regulatory codes are cited as reasons for a customized solution. In the latter case, a systems approach is required, especially when attempting to meet the code or performance requirements for compliance with European Certification (CE) mark or electrical and fire safety codes such as National Eire Prevention Association (NFPA) and CENELEC (European Committee for Electrotechiucal Standardization). Off-the-shelf electronics may provide the necessary performance characteristics for generic applications, and their use eliminates large expenses related to product development, plus the associated time delays. Photonics-related components are solely addressed in this section because they are used to customize instruments for application-specific systems. 

Source and detector selection are interrelated, where the output of the source is matched to the sensitivity range of the detector. However, the exact nature of the source is also dependent on the type of sample(s) under consideration, the intended optical geometry, the type of measurement technique, and the final desired performance. The bottom line is that adequate source energy must reach the detector to provide a signal-to-noise performance consistent with the required precision and reproducibility of the measurement. This assumes that the detector is well matched, optically and performance-wise, and is also capable of providing the desired performance. 

Most optical spectral measurements, where the measurement of multiple wavelengths is required, will feature some type of polychromatic or broadband light source. There are a few exceptions here, such as tunable laser sources and source arrays. In such instances, the source is effectively monochromatic at a given point in time. These sources are covered separately under monochromatic sources. 

The other forms of blackbody sources are adaptations of those used widely in conventional laboratory-style IR instruments, which feature exposed electrically heated elements. Various designs have been used, with metal filaments, made from Kanthral and Nichrome, being simple solutions in lower cost laboratory 

Most optical spectral measurements, where the measurement of multiple wavelengths is required, will feature some type of polychromatic or broadband light source. There are a 

---