TABLE OF CONTENTS In the following section, a variety of optical sensors and techniques are described. However, the objective of this chapter is to make the reader aware of the vast possibilities and the recent developments on the subject from a systems based point of view only, rather than to shed light on the fundamental problems encountered by current research.
Optical measurements can generally be classified in the following categories:
Imaging methods which are based on the recording of the spatial distribution of the light intensity, such as photography and microscopy.
Interference methods based on the recording of the spatial distribution of the intensity and phase (energy and momentum) of the light waves, such as light interferometry and atom interferometry.
Light scattering methods which are based on the measurement of the spatial and local features of scattered light using either single particle counters or performing particle concentration measurements based on diffraction, or rate of polarisation effects.
After a brief introduction to some commonly used coherent and incoherent sources, and some stabilisation techniques, a variety of detectors commonly used in sensor applications are described. Emphasis is then given to scattering techniques and the most commonly used spectroscopies, which very often may simultaneously incorporate a variety of modulation principles. Next, the different measurement techniques for the determination of electric dipole polarisabilities and some recent applications based on the interaction of light with matter, including the latest advances in THz measurement and instrumentation systems, are...
