Photoluminescence imaging of speleothem microbanding with a high- resolution confocal scanning laser macroscope

• Published in: Quaternary international 2000-01, Vol.68-71, p.253-259
• Main Authors: Ribes, A.C, Lundberg, J, Waldron, D.J, Vesely, M, Damaskinos, S, Guthrie, S.I, Dixon, A.E
• Format: Article
• Language: English
• ISSN: 1040-6182; 1873-4553
• DOI: 10.1016/S1040-6182(00)00048-3

Micron level resolution is required to image tightly spaced annual bands in speleothems. These same bands must be viewed over several millimeters and sometimes centimeters in order to ensure continuity. We report luminescence imaging results from several speleothem specimens using a novel confocal scanning laser macroscope instrument. The macroscope can non-destructively image specimens as large as 7.5×7.5cm using reflected light and photoluminescence with a 10μm lateral resolution in under 10s. A high-resolution version of the macroscope can image specimens up to 1–2cm in size with lateral resolutions ranging from 1 to 2μm depending upon the laser scan lens utilized. The combination of both these instruments allows for entire specimens to be imaged even beyond 7.5×7.5cm fields of view via tiling. Confocal imaging improves overall resolution of the instrument by eliminating light originating from outside the focal plane which tends to blur the image. High-contrast, crisp images are achieved in this way. We show photoluminescence imaging results for speleothem specimens where emphasis is placed on resolving to the level of annual bands.