| Abstract [eng] |
Luminescence is the light emitting process when an electron jumps from excited to a ground state. In undoped laser host material luminescence could be generated in various ways: using optical filaments, accelerated electrons (cothodoluminescence), X-ray beam (X-ray luminescence), etc. In this work we are using filaments of light in order to induce luminescence and observe the resulting spectrum. This method is more convenient compared to cathodoluminescence or X-ray luminescence because the specimen is excited by laser beam. In this way, we have a system which is easily adjustable, requires no complex optical elements and no vacuum chamber is needed. Besides, it allows to study decay of excited states which is not possible during other experiments. Use of filaments in luminescence spectroscopy could be nondestructive way to examine transparent solid material in order to determine it's quality. Luminescence was generated by using filaments of light. High intensities are needed are needed to generate it and yet no optical damage should be induced in the specimen. In this experiment these intensities are reached by focusing femtosecond laser pulses into the specimen. The peak intensity of the filament is sufficient to excite impurities and charge carriers in the material. The filament induced luminescence from both surface and volume is observed and registered from the side of the filament. The main purpose of this work is to perform spectral and time resolved measurements in most popular undoped laser host materials such as YAG, Al2O3, KGW and estimate method suitability in order to investigate purity of laser host materials. Specimens were provided by different manufacturers. |
