Preparation Of Ho³⁺ Doped Fluoride Glass Fibers And Their Applications In ².9 ?m Fiber Laser

Lasers operating at around 2.9?m have attracted much attention due to their significant applications in spectroscopy,medical treatment and environmental monitoring.To date,².9?m lasers based on glass or glass fibers have only been obtained by using ZrF4-BaF2-LaF3-AlF3-NaF?ZBLAN?glass and fibers as the gain media.However,ZBLAN glass was easily reacting with water,which would affect the applications of ZBLAN fiber devices to some extent.Therefore,to improve the performance of 2.9?m fiber lasers,it is very important to explore new mid-infrared glass fibers with low phonon energy,good chemical and thermal stabilities and investigate their application in 2.9?m fiber lasers.During the Ph.D,the author had a systematic study on the exploration of fluoride glasses with low phonon energy and good capability of water proof,designing and preparation of Ho³⁺-doped fluoride glass fibers and investigating the application in 2.9?m fiber lasers of Ho³⁺-doped fluoride glass fibers,the obtained research results were listed as follows:?1?Under the excitation of 1120 nm laser,efficient 2.9?m emissions were observed from Ho³⁺-doped ZnF2-based glasses.The ZnF2-based glasses had low phonon energy(⁴20 cm^-1)and broad transmission window?0.3¹2.8?m?.The obtained 2.9?m emission intensity from Ho³⁺-doped ZnF₂-based glasses was much stronger than that in Ho³⁺-doped fluoroaluminate,fluorozirconate and fluoroindate glasses under the same excitation density and the Ho³⁺-doped ZnF2-based glasses had a large full width at half maximum?¹24 nm?of the 2.9?m cross section.?2?We fabricated Ho³⁺-doped fluoroindate glass fibers by using rod-in-tube method for the first time,and we obtained 2875 nm lasing by using Ho³⁺-doped fluoroindate glass fibers as the gain medium.In the experiments,the pump source was a 1120 nm fiber laser,the gain fiber length was 92 cm.As the launched pump power was 1224 mW,the obtained output power of 2875 nm laser was 54.5 mW and the corresponding slope efficiency was 6%.?3?Based on the fluoroaluminate glasses with good capability of water proof and thermal stability,we fabricated Ho³⁺-doped fluoroaluminate glass fibers for the first time.We obtained 2875 nm lasing by using Ho³⁺-doped fluoroaluminate glass fibers as the gain medium.In the experiments,the gain fiber length was 84 cm and a 1120nm fiber laser was used as the pump source.The threshold pump power was 140 mW and the maximum unsaturated output power was 57 mW with a slope efficiency of 5.1%.