Studies On Mid-infrared Emission Properties Of Rare Earth And Transition Metal Ions Doped Chalcogenide Glass Ceramics

Mid-infrared gain materials are the fundamental part of laser,ultrashort pulsed laser and frequency comb,so it is of great importance in mid-infrared photonics to develop novel mid-infrared gain materials.With low phonon energy and broad transmission window,chalcogenide glass is an ideal host for the mid-infrared emission of rare earth and transition metal ions.And the chalcogenide glass ceramic combined the high quantum efficiency of active ions in crystals and excellent physico-chemical stability,as well as strong forming ability of chalcogenide glass,occupying the significant status in mid-infrared luminescent glass ceramics.In this dissertation,infrared phonics developments of chalcogenide glass(Ch G)and chalcogenide glass ceramic(Ch GC)were reviewed,and the mid-infrared photoluminescent properties of rare earth ion and transition metal ions doped Ch GC had been studied as follows:(1)The mid-infrared emission of rare earth ion in Ch GC is stronger than that in base glass.such enhancement mechanism dependent on where the rare earth ions to reside in Ch GC,both of which are controversial issues.In this work,the distribution of Tm³⁺ion was evidently observed by high resolution TEM,enlightening the controversial issue.Then the mid-infrared emission of Tm³⁺ion in Ch GC was studied,and the luminescent enhancement mechanism of rare earth ions was further elaborated according to observed distribution.(2)Divalent transition metal ions doped II-VI crystals are endowed with ultrabroadband mid-infrared emission,but the notorious thermal lens effect in crystals restrict quality of the laser beam.With unique advantage in thermal management,fiber laser can tackle the issue.So the II-VI crystal was proposed to melt with Ch G by conventional melt quenching method,and to prepare Ch GC by further heat-treatment,which can pave the way for Ch G fiber.First attempt was based on As₂S₃glass host,and the crystallization behavior,network structure and thermo-mechanical properties of the novel Ch GC were studied,then those studies on Ge_1.5As₂S_6.5based Ch GC were also carried out and the properties of the latter host was found much better than the former one,for example,the crystallization volume elevated to 4%.Furthermore,pumped by 1.57?m commercial fiber laser,broadband mid-infrared emission of Cr²⁺ions was achieved in this novel Ch GC.(3)Co²⁺ions doped Ch GC was studied and the obtained broadband mid-infrared emission of Co²⁺can offset the 3?4?m luminescent gap of Ch GC.Then the crystal field engineer strategy was utilized to tailor the emission properties,including peak wavelength and full width at half maximum of the emission of Co²⁺ions.(4)Fe²⁺doped II-VI crystal have the 3.0?5.5?m emission,which beyond the bounds of Cr²⁺and Co²⁺.But Fe²⁺ion is hard to pump because of the scarce 3?m excitation source.With the help of high-efficiency energy transfer of Co²⁺?Fe²⁺,2.5?5.5?m broadband mid-infrared emission of Fe²⁺ion was achieved in the novel Ch GC pumped by the commercial 1.57?m light source.The efficiency of energy transfer was found anomalously improved with increasing temperature.Moreover,gas sensing application was demonstrated by butane,suggesting the great potential of the novel Ch GC in gas sensing.To sum up,conclusions drawn herein greatly enlightened the hot topic that the distribution of rare earth ions in Ch GC,and the study on the near infrared emission of Ni²⁺in Ch GC enrich the studies about the influence of crystal site on dopants.Furthermore,novel Ch GC embedded with II-VI nanocrystals was proposed in this dissertation,intensive studies on whose transmission,thermal-mechanical,crystallization behavior and mid-infrared optical properties were carried out.2?5?m emission of divalent transition metal ions,including Cr²⁺,Co²⁺and Fe²⁺,had been achieved in the novel Ch GC,suggesting that such a novel Ch GC is a promising material for mid-infrared photonics and cost-efficient,portable gas sensor.