Investigation On Mid-infrared Spectroscopic Properties Of Ho³⁺ Doped Chalcogenide Glasses

2-5μm mid-infrared covers many important molecular vibrational absorption bands, such asbiological tissue, ground, air pollutants, toxic agents, oil and so on. Therefore, mid-infrared sourcesare of great interest for biophotonics, real-time monitoring, remote chemical sensing andmid-infrared radar. Rare-earth doped matrix glasses and optical fiber are effective ways to obtainmid-infrared sources. As hosts for rare earth ions, the low phonon energy （<350cm-1）ofchalcogenide glasses allow many mid-infrared and long-wave IR rare earth transitions that arenormally quenched in silica and fluoride glasses to became active. Furthermore, the high refractiveindex and wide infrared transmittance of chalcogenide glasses allows the potential for2-5μmmid-infrared laser. In recent years, chalcogenide glasses have been proposed as potential hostmaterials for RE-doped lasers and amplifiers.On the basis of the previous researches,2-5μm mid-infrared spectroscopic properties werestudied in Ho³⁺-doped chalcogenide glasses and chalcohalide glasses. The Ge-In-S-CsI andGe-Ga-Sb-S glass systems have been studied. The optical parameters by means of Judd-Ofelttheory according to absorption spectrum were calculated in different glasses, the emissionproperties at2-5μm range were investigated with different Ho³⁺ion concentration. Based on theHo³⁺, Tm³⁺/Ho³⁺ion transition system in matrix glasses, a fiber amplifier mode is performed. Anumber of simulations have been made in order to evaluate the actual feasibility of the Ho³⁺dopedchalcogenide amplifier. The gain properties in Ho³⁺single doped and Tm³⁺/Ho³⁺co-doped matrixglasses were discussed, and the relationship among the gain, the pump power and doped fiberlength were discussed. All these work provide enough experimental foundation and theoreticalbasis for the realization of2-5μm mid-infrared emission in chalcogenide glasses.In chapter one, the development of2-5μm mid-infrared radiation was introduced. This partfocuses on the mid-infrared emission in rare earth and Ho³⁺ion doped chalcogenide glasses.Advances in the application of mid-infrared and fiber amplifier were analyzed. The purpose andsignificance of this thesis are also summed up in this chapter.In chapter two, mainly introduced the theoretical background, including two aspects, one isJudd-Ofelt theory, Futchbauer-Ladenburg and Mc-Cumber theory, the other one is fiber amplifiertheory, such as four energy level system, energy transfer, rate equation theory and so on.In chapter three, the experiment methods were studied, mainly consist of the glass samplepreparation, and the measurement methods of optical properties. In chapter four, a series of Tm³⁺/Ho³⁺co-doped GeS2-In2S3-CsI chalcohalide glasses wereprepared. With the increase of the Ho³⁺ion concentration, the2.0μm fluorescence properties ofglass samples were investigated. Also the energy transfer between Tm³⁺and Ho³⁺ions werediscussed.In chapter five, the gain properties of Ho³⁺doped chalcogenide glass in mid-infrared emissionat2.86μm were studied. On the basis of the optical characteristics in Ho³⁺doped glass includingabsorption spectrum and emission spectrum, established the theoretical glass fiber amplifier model.The feasibility of the holmium doped GeGaSbS glass fiber amplifier at2.86μm has beendemonstrated. The results indicated that the amplifier mode with high gain.In chapter six, the gain properties of Tm³⁺/Ho³⁺co-doped chalcogenide glass at2.0μm werestudied. The spectral parameters （emission cross section, radiative life, etc.） were calculated. Basedon the two ions energy level transitions, a glass fiber amplifier model at2.0μm was build. Themodel takes into account the effects of energy transfer, up-conversion, ground-state absorption, andso forth. Finally, discuss the gain properties.In the end, all the results of this work are outlined, and some improvements should be done inthe future work.