1. Optical dating in a new light: A direct, non-destructive probe of trapped electrons
- Author
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N.R.J. Poolton, Amit Kumar Prasad, Mayank Jain, and Myung Ho Kook
- Subjects
010506 paleontology ,Mineralogy ,lcsh:Medicine ,Electron ,Feldspar ,01 natural sciences ,Signal ,Article ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Optics ,lcsh:Science ,Quartz ,Image resolution ,0105 earth and related environmental sciences ,Physics ,Multidisciplinary ,business.industry ,Relaxation (NMR) ,lcsh:R ,visual_art ,visual_art.visual_art_medium ,lcsh:Q ,business ,Optical dating ,Excitation - Abstract
Optical dating has revolutionized our understanding of Global climate change, Earth surface processes, and human evolution and dispersal over the last ~500 ka. Optical dating is based on an anti-Stokes photon emission generated by electron-hole recombination within quartz or feldspar; it relies, by default, on destructive read-out of the stored chronometric information. We present here a fundamentally new method of optical read-out of the trapped electron population in feldspar. The new signal termed as Infra-Red Photo-Luminescence (IRPL) is a Stokes emission (~1.30 eV) derived from NIR excitation (~1.40 eV) on samples previously exposed to ionizing radiation. Low temperature (7–295 K) spectroscopic and time-resolved investigations suggest that IRPL is generated from excited-to-ground state relaxation within the principal (dosimetry) trap. Since IRPL can be induced even in traps remote from recombination centers, it is likely to contain a stable (non-fading), steady-state component. While IRPL is a powerful tool to understand details of the electron-trapping center, it provides a novel, alternative approach to trapped-charge dating based on direct, non-destructive probing of chronometric information. The possibility of repeated readout of IRPL from individual traps will open opportunities for dating at sub-micron spatial resolution, thus, marking a step change in the optical dating technology.
- Published
- 2017
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