Use of dual-color optical pyrometry for determining the characteristics of flying nonpoint condensed-phase particles produced during laser ablation of leucosapphire

Subject of study. This study investigates the influence of aberrational distortions introduced by the optical system of a dual-color spatial pyrometer with mutually perpendicular registration channels on the determined characteristics of flying nonpoint condensed-phase particles formed during the laser ablation of leucosapphire, whose diameters exceed the spatial resolution of the pyrometer. Aim of study. This study aims to develop a methodology that enables simultaneous determination of temperature, luminescence characteristics, and physical size along the flight trajectory of hot flying nonpoint particles, considering optical aberrations. Method. The aberration characteristics of each channel of the optical system within the observation region of the pyrometer were determined using objects simulating the streaks of moving hot particles. The experimental data acquired from each registration channel were subsequently processed considering the introduced aberrational distortions. Main results. The developed methodology enabled investigation of nonpoint particles, including determination of the evolution of their physical size during flight in the case of observation in two channels; characterization of transformations occurring in moving hot particles; reconstruction of the complete three-dimensional trajectory of a particle recorded in a single channel; and calculation of the effective temperature associated with the surface regions of a flying particle. Practical significance. The proposed approach can be applied in the use of pyrometers for the development and implementation of technological processes involving laser ablation, including three-dimensional printing, welding, and coating deposition. This approach enables rapid monitoring of the parameters associated with the resulting condensed-phase particles and optimization of the process parameters.