Illustration of ARSMS for detecting cylindrical test mass in cylindrical coordinates. Note: the size of the translation platform is about and the size of the rotational platform is about .
Illustration of mapping layer-by-layer Rayleigh scattering images within the test mass. A laser beam is first passed through the center of the sample to take a single beam image [the scattered light is at right angles (90°) to the laser beam]. The computer controlled translation platform moves the sample along the radius with step length comparable to the laser beam size (in our case, ). A single beam image is taken by the CCD camera at each step. Then the sample is rotated by successive degrees around the center axis of the sample to scan another section. This process is repeated until we obtain a complete set of line images of the sample (see Ref. 9).
Communication with the processing image system. Here is the layer number which you intend to map while is the scanning line number in each layer. is the position where the laser beam passes through the sample in cylindrical coordinates.
(a) Typical Rayleigh scattering map of a cross section in sample 1. Due to the small high intensity point defects it is best shown as a 3D plot. (b) A similar map for sample 2. Due to the small range of scattering the image is presented as a false colour plot. (c) The inhomogeneous structure in sample 2 is due to changes at the crystalline growth boundary during manufacture, as can be seen when the image is reconstructed into a cylindrical form. The image shows the conical shape of the solid liquid interface of a growing boule.
Graphical user interface created in Visual Basics for the system. Note: all of the parameters in the interface are the default values and can be changed according to the actual situation, such as the size of the sample, the intensity of scattering, etc.
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