LIGHT EMITTING DIODES AND OPTICALLY STIMULATED LUMINESCENCE DATING IN ARCHAEOLOGY: AN OVERVIEW
Keywords:
Luminescence, LED, chronology, semiconductors, dopants, archaeology, nobel prize, blue green IR light.Abstract
Among the multiple applications of Light emitting diodes (LEDs), archaeology and earth sciences have benefited too concerning the determination of time (chronology) based on the thermoluminescene (TL) and optically stimulated luminescence (OSL) method of dating artifacts, material culture of archaeological and geoarchaeological significance. Blue Light emitting diodes (LED) is mostly used for stimulation and bleaching of luminescence, in lieu of green and IR LEDs. Ancient inorganic materials made of geological rocks (carving, knapping, mixing, firing) are either fired in antiquity above 450 o C or sun exposed for a short time (surface luminescence dating) and thus the electron traps are completely bleached for the “zero time” clock to set up. The importance of blue LEDs in archaeology was the research product of 2014 Nobel Prize in Physics. On the occasion of blue LED invention and Nobel Prize we offer an extended overview of the development of semiconductor physics focused on LEDs (blue, green, IR) and linked to the principles of OSL dating in archaeology.
