The stone surface topography is laser scanned, by using the 405 nm laser scanning mode, within the Axio Imager.Z2m LSM 800 microscope (Carl Zeiss GmbH, Germany), running the software Zen Blue 2.5 (Carl Zeiss GmbH, Germany). The LSM 800 laser module LM URGB (contains fibre-coupled, pigtailed and collimated lasers) is turned on and the anti-vibration table Vision IsoStation (Newport, USA), on which the microscope system is positioned, is filled with 1 bar of pressure using compressed air. The manual tube slider (for switching between VIS/Camera) is placed into the camera position (100 % camera). Within the applications tab of the Zen Blue 2.5 software, under the »topography«, the image acquisition option is selected. The intensity of the 405 nm violet diode laser (5 mW, class 3B), used for scanning, is set to 10 %. The pinhole is set to 1 Airy unit (AU) with an opening diameter of 25 µm, and the master gain is set 250 V. Detection is via the LSM 800 MAT Confocal MA-detection module (Carl Zeiss GmbH, Germany), which consists of a main beam splitter (MBS), a variable pinhole with automatic alignment, two variable secondary dichroics (VSD) placed at 10 degree angle to incident beam for most effective excitation light suppression; and an emission filter in front of each of the two multi-alkali (MA) PMT confocal channel detectors. In order to engulf the entire surface topography, the scanning borders (set first/last) are set to acquire a 700 µm long interval of Z-stack images (each image is 0.41 µm apart) and these are saved as a CZI file format. This format is them opened within the ImageJ distribution Fiji, and the images are reduced to 8-bits. Finally, by selecting the 3D Viewer option, within the »Plugins« menu, a 3D surface topography model is generated. Moreover, from the CZI file format, surface roughness parameters are calculated in Fiji. These include the root mean square deviation (Rq; [µm]), and the arithmetical mean deviation (Ra; [µm]) and many more. For their calculation, a height map is generated, by selecting the »Extended depth of field (EDF easy mode)« option within the »Plugins« menu. Based on the levelled surface of this map, the »SurfCharJ 1q« plugin calculates the above parameters.

3d laser scanning

3D micro-topography of surface

Micro-surface analysis

2023