A novel crystal Tm: Lu0.8Gd0.8Y0.4SiO5 with potential for broadband tunable lasing

A novel Tm3+ -doped crystal Lu0.8Gd0.8Y0.4SiO5 (Tm: LGYSO) was grown by the Czochralski (Cz) method. The full width half maximum (FWHM) of the Tm:LGYSO crystal around 2 μm was as broad as 280 nm, which is the broadest FWHM among the Tm3+ doped crystals have been reported, to the best of our knowledge. The crystal growth, structure, absorption spectra, J-O parameters, emission spectra and fluorescence lifetime were discussed in details. The absorption cross-section is 1.429 × 10−20 cm2 and the full width half maximum is 8.337 nm at 791 nm. The spectroscopic parameters were calculated using the Judd-Ofelt theory, and the J-O parameters Ω2, Ω4 and Ω6 were found to be 1.615 × 10−20, 2.773 × 10−20 and 0.695 × 10−20 cm2, respectively. An intensity and broad 2 μm emission of the 3F4 → 3H6 transition in Tm: LGYSO crystal was observed with an emission cross-section of 0.73672 × 10−20 cm2 at 1972 nm. The fluorescence decay time of the 3F4 → 3H6 transition was measured to be 1.669 ms. Results suggest that Tm: LGYSO crystal is a promising laser crystal for tunable and ultrafast laser output around the 2 μm wavelength.