Fiber optic probes collect light or spectra from extreme environments inside reaction vessels at high temperatures or pressures. Product types include UV-Vis spectroscopy probes, Raman spectroscopy probes, and refractometry probes. UV-Vis spectroscopy probes track the electronic transitions of molecules as they absorb light in the ultraviolet (UV) and visible (Vis) regions of the electromagnetic spectrum. These fiber optic probes can be used with a wide range of samples and are suitable for biochemical, biological, and pharmaceutical research. Raman spectroscopy probes collect scattered light from a sample that is illuminated with a laser. Molecular components are identified through an analysis of the wavelengths and intensities of the scattered light. Because of their ability to avoid sample contamination, Raman spectroscopy probes are often used in polymer and semiconductor applications. Refractometry probes are fiber optic probes that detect the deviation of light by a solution as a measure of specific gravity. They are sometimes used in the identification of gemstones.

Fiber optic probes differ in terms of optics technology. Choices include holographic optics, immersion optics and insertion optics. Holographic optics produce a hologram through the use of high-precision optical hardware such as collimators, mirrors, spatial filters, optical lenses, camera lenses, exposure meters and beam splitters. Immersion and insertion optics feature single, double or triple-window designs and can be directly inserted into high-temperature reaction vessels and process streams. Like holographic optics, immersion optics and insertion optics provide high signal-to-background measurements along various lengths of optic fiber. Optics working distance and optical fiber specifications are also important considerations when selecting fiber optic probes. As a rule, single fibers or single collection fibers are less expensive than multi-fiber fiber optic probes. In some products, standard telecommunications fibers are used to provide enhanced mechanical stability.

Fiber optic probes differ in terms of applications. Raman spectroscopy probes can be used to analyze samples, obtain chemical intermediate information from automated laboratory reactors, monitor in-situ crystallization, detect end-points, and identify polymorphs. UV-Vis spectroscopy probes are available in both dual beam and diode array designs. Dual-beam fiber optic probes offer superior flexibility and precision. Diode array fiber optic probes combine flexibility with relatively high speeds. Refractometry probes are used in medical fields such as hematology.