Preparation And Temperature Sensing Properties Of Rare Earth Doped Tungsto-Tellurite Glasses

As information measurement technology products play an indispensable key role in the global informationization process,the advancement of sensor technology has become the key to today's new technological revolution and information society.In recent years,with the continuous improvement of temperature control and monitoring requirements in the industrial field,new fiber optic temperature sensors such as semiconductor absorption type,F-P interference type,fiber grating?FBG?,and distributed have emerged.Among them,the combination of fluorescent fiber temperature fluorescence temperature measurement technology and fiber technology.Because it has the advantage of eliminating the influence of fluctuations in the intensity of the light source,the structure is simple,and the cost is low,it has attracted extensive attention in the scientific research community.The core of the research of the fluorescence temperature sensor is a fluorescent material,such as a rare earth doped fluorescent material,which emits longer wavelength visible light,that is,fluorescence,under excitation light.The choice of fluorescent material determines the temperature range,sensitivity and stability of the sensor.Referring to the previous literature,it is known that tungsto-tellurite glass has low phonon energy,low melting temperature,high refractive index,and rare earth doping solubility,and is the material of choice for sensor applications.In this thesis,a novel point-type all-fiber temperature sensing device is designed and built based on the fluorescence intensity ratio.?1?TWG glass was prepared by high-temperature solid-state reaction method.The X-ray diffraction pattern?XRD?confirmed the morphology of the glass.The differential thermal and Raman tests proved that the tungsten-rhodium glass has high chemical stability and thermal stability.It is used to calibrate the thermometer.The thermometer operates over a temperature range of 300-600K,and it exhibits excellent linearity?r²>0.99?and low accuracy over this temperature range.By optimizing the Er³⁺concentration,we can obtain high green radiation intensity and high thermal sensitivity of the probe.The highest temperature sensitivity of the fitting is97.8×10^-4K^-1 at 560K.It shows that the probe made of tungsten glass shows better performance as a temperature sensor application.?2?Er³⁺/Yb³⁺co-doped yttrium-tungsten-rhenium glass was prepared by high-temperature solid-state reaction.XRD and fluorescence spectroscopy tests are used to find the best luminescence concentration and optimal temperature sensing sensitivity.The high glass transition temperature?T_g=439??of bismuth tungsten strontium soda glass can expand the temperature measurement range.Spectral analysis of the Jud-Ofelt theory of Eu³⁺ions shows that the rare earth ions are located in a low symmetry environment of bismuth tungsten strontium soda glass,indicating that the expected fluorescence intensity ratio will vary greatly and the sensitivity of the sensation will increase.Er³⁺/Yb³⁺co-doped yttrium-tungsten-doped sodium glass fibers are easily observed at 980 nm excitation,although they are easily observed at very low pump powers?1.4 mW?.The maximum temperature sensitivity of the portable all-fiber thermometer is 86.7×10^-4 K at a temperature of 553 K.The experimental results show that the absolute error is around 1K in the temperature range of 285-564K.?3?A new point-type all-fiber temperature sensing device was designed and constructed,which consisted of a 980 nm fiber laser,a wavelength division multiplexer?WDM?,a spectrometer and a computer display.The temperature detection probe uses the direct fusion technology of the fluorescent material glass filament and the sensing fiber to greatly improve the stability of the fiber temperature sensing probe.At 1 mW of 980 nm pump light,bright green light was observed.