Optical radiation, delivery

Fig. 1 Accessories for diffuse reflectance spectroscopy (A) Integrating sphere with hemispherical radiation collection (B) Accessory based on ellipsoidal mirrors, used within the sample compartment of the spectrometer (C) Rotational ellipsoidal mirror device with dedicated detector and (D) Bifurcated fiber optic-based accessory (also shown is the random mixture of fibers for illumination and detection compared with devices based on reflection optics the acceptance cone for radiation delivery and collection is limited and depends on the refractive indices of the core and cladding material).

The most common UV-vis spectrometers are designed to accept samples in glass or quartz cuvettes, 1 cm on a side. Fiber optics now allow remarkable versatility in how the radiation is transmitted to the sample and returned to the spectrometer. Dip probes combine two optical fibers for the delivery and return of the radiation, with a tiny sample compartment and mirror arrangement at the probe tip, allowing the probe to sample analytes in a wide range of environments. 

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