Influence of Low Al/Tm Ratio on Spectroscopic Properties and Color Centers in Thulium-Doped Silica Glasses

The main tests involved in this data include: density measurement using an electronic density tester (SD-200L) based on the Archimedes method, and refractive index measurement using a waveguide prism coupling instrument (2010/M). Inductively coupled plasma atomic emission spectroscopy (ICP-AES) was used to measure the actual Tm and Al element content in glass samples. The absorption spectrum was tested using a spectrophotometer (Perkin Elmer Lambda 950) with a wavelength range of 200-2000 nm, a scanning step size of 1 nm, and a glass thickness of 2 mm. The fluorescence spectrum of the glass sample was tested using a high-resolution fluorescence spectrometer (FLS920) with an excitation source of 793 nm laser diode. The fluorescence lifetime decay curve was tested using FLS1000 fluorescence spectrometer, with a 793 nm pulse laser as the excitation source and a pulse width of 4 µ s. The Fourier transform infrared spectrometer (Nicolet 6700) was used to measure the infrared transmittance spectrum of the glass sample, with a testing range of 400-4000 cm-1. The glass sample was irradiated using an X-ray irradiation system (MultiRad 160) with a total cumulative irradiation dose of 500 Gy and a dose rate of 10 Gy/min. Grind the irradiated glass into powder, take 200 mg of powder sample and test the continuous wave paramagnetic resonance spectrum at room temperature using an X-band EPR spectrometer (Bruker E580) with a testing range of 344-360 mT. Use a Bruker Avance III HD 500 MHz nuclear magnetic resonance spectrometer to test the 27Al MAS-NMR spectrum, using a 4mm Bruker magic angle rotation (MAS) probe with a resonance frequency of 130.4 MHz and a rotation frequency of 12 kHz. The 10 ° pulse length is 0.72 µ s, and the relaxation time is 2 s. The chemical shift of the 27Al spectrum is calibrated with a 1 mol/L Al (NO3) 2O3 solution.