Luminescence depletion imaging of SrAl₂O₄:Eu²⁺, Dy³⁺ using solid state laser in dark field microscopy

Numerous studies have been conducted on the SrAl₂O₄:Eu²⁺, Dy³⁺ phosphor (SAOED). One feature frequently ignored is that the radiation from the laser in this phosphor turns off the luminescence emission, which may impact these materials' potential applications. We studied the photoluminescence (PL) emission behavior of SrAl₂O₄:Eu²⁺, Dy³⁺ phosphor under laser irradiation. The results show that lasers deplete the luminescence. Experimental results showed that applying of 532 nm and 660 nm lasers resulted in a depletion in emission intensity. This depletion was confirmed by histograms and 3D intensity plots, which revealed a shift toward lower intensity values. Additionally, the phosphor coated with SiO₂ showed successful encapsulation, was validated by SEM and EDX analysis, and the photoluminescence spectra showed a slight decrease in emission intensity due to the silica coating. The purpose of this study is to implement a method for suppressing luminescence emission using a laser and apply it to microscopic applications and chemical analysis. This method involves laser-induced depletion of sample luminescence emission and dark-field imaging. The combination of spectroscopic, microscopic, and image processing methods allows for sample observation and analysis. The purpose of this project is integrating these techniques to provide an efficient approach to studying and analyzing samples at a microscopic level.