Crystal growth, structural and spectroscopic characterization of undoped and Yb3+-doped oxyboroapatite fibers

Abstract

High quality undoped and Yb 3+ -doped new calcium oxyboroapatite single crystals were obtained. The samples were grown in monocrystalline fiber form by using a fast and economical floating zone method under laser heating so-called LHPG for laser heated pedestal growth and were characterized by X-ray diffraction, IR spectroscopy and Raman spectroscopy. Yb 3+ absorption, emission and fluorescence decay studies were carried out both at low and room temperatures. Electronic energy level positions were interpreted by comparing absorption and emission spectra with those of vibronic sideband energy positions from Raman and IR absorption spectroscopies. Emission spectrum at low temperature and experimental fluorescence decays within ms range reveal Yb 3+ ion occupation within at least two different crystallographic sites of the apatite-type structure leading to a broad emission band at room temperature from 925 to 1200 nm, which seems of high interest for ultrashort laser pulse production.