The LIDT raster scan test helps to detect very rare defects on the sample surface.
Test procedure:
The sub-aperture Raster Scan test is often used for investigating LIDT. Covering a significant portion of the sample area (typically 1 cm²), a moving laser beam scans the surface with spatial overlap between test sites. The overlap ensures that at least 90% of peak fluence is consistently applied across the entire test area. Before the test and after each scan, the surface is examined under a microscope for damage. If no damage is found, the scan is repeated with increased peak fluence on the same area. This process continues with incremental irradiation level adjustments until damage is detected or the system's maximum level is reached. This test, when conducted beyond the damage initiation threshold, can also reveal insights into damage density versus irradiation level.
Learn more: LIDT raster scan procedure