Crystal growth and spectral properties of Tm, Ho : CaGdAlO4 crystal

Abstract

2 μm pulsed lasers not only have critical applications in military, medical, and processing fields but are also an important frontier in laser physics. The development of these pulsed lasers has been hindered by the lack of laser crystals with both high thermal conductivity and broad spectral properties. In this work, Tm, Ho : CaGdAlO₄ disordered crystal with ultra-broad emission spectra around 2 μm was achieved successfully by modulating the emission intensities of Tm³⁺ and Ho³⁺ ions to the same level. The FWHM of the absorption spectra at 793 nm for the 〈001〉 and 〈100〉 directions are 18.69 and 19.44 nm, respectively, which is beneficial for commercial laser diode pumping. More importantly, the FWHM of the emission spectrum is 264 nm, which is the widest one reported in the previous literature. The results indicate that the Tm, Ho : CaGdAlO₄ crystal with its broader spectra has the potential to generate an ultrashort pulse laser.