Light signalling, history

This article reviews all the published work concerned with the study of vibrational optical activity in chiral molecules from measurements of a small difference in the intensity of Raman scattering in right and left circularly polarized incident light. The history and basic theory are described briefly, followed by an account of the instrumentation and the precautions that must be observed in order to suppress spurious signals. The various theories that have been proposed in order to relate stereochemical features to the observations are then outlined, this being followed by a survey of all reported Raman optical activity spectra. 

In principle reactions that are induced by a light signal could be in the conventional time range, or rapid, requiring rapid data acquisition. The latter class of reactions became a reality in the history of this research area upon the development of fast... 

This has led to such cases in the history of chemistry that spectroscopic signals have been unidentified till newly discovered elements was found (e.g. rubidium, caesium, indium, helium, rhenium) or new species (highly ionized atoms, e.g. in northern lights [aura borealis], luminous phenomena in cosmic space and sun aura, such as nebulium , coronium , geocoronium , asterium , which was characterized at first to be new elements see Bowen [1927] Grotrian [1928] Rabinowitsch [1928]). 

It would not be an exaggeration to say that the history of plastic optical fibers (POFs) has been a history of the attempts to reduce their transmission loss. The transmission loss limits how far a signal can propagate in the fiber before the optical power becomes too weak to be detected. It measures the amount of light lost between the input and output it is normally expressed in decibels and defined as... 

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