2.8 μm Er ∶ZBLAN中红外光纤激光器研究

中红外波段激光光源在环境监测、材料加工、外科手术、军事等领域发挥重要作用。泵浦低损耗、高浓度Er³⁺掺杂ZBLAN(Er ∶ZBLAN)光纤是产生近3 μm激光输出的主要手段之一,相较于其他同波段固态激光器,Er ∶ZBLAN光纤激光器具有易集成、效率高,可采用激光二极管直接泵浦等优势,性能日渐提升的Er ∶ZBLAN光纤激光器有望成为3 μm波段最先发展成熟、走向应用的激光光源。本文主要介绍Er ∶ZBLAN光纤激光器工作原理和发展现状,对三种不同的Er ∶ZBLAN光纤激光器存在的问题进行分析和总结,最后对Er ∶ZBLAN光纤激光器发展趋势进行展望。     

Dy3+掺杂Ga-Sb-La-S新型硫系玻璃和光纤制备及中红外发光特性

制备了一系列新型Ga2 S3-Sb2S3-La2S3硫系玻璃,研究了玻璃的热学和光学性能;向优化的玻璃中掺杂Dy3+,研究了玻璃的中红外发光性能;基于优化的玻璃组成,拉制了纤芯/包层结构光纤,评估了其作为中红外激光增益介质的潜力.实验结果表明,Ga2S3-Sb2S3-La2S3玻璃具有宽的红外透过范围(约0.7 ～13.6 μm)和高的线性折射率(约2.655 ～2.707),组成为20Ga2 S3-75Sb2 S3-5La2S3的玻璃具有最佳的抗析晶热稳定性.Dy3+掺杂的玻璃在2.95 μm和4.40 μm具有较高的发光量子效率和较大的受激发射截面.拉制的20Ga2 S3-75Sb2S3-5La2 S3∶0.05wt％Dy3 +/20Ga2 S3-74Sb2 S3-6La2 S3光纤透光范围为2～8 μm,其背景损耗＜8 dB/m.在1.32 μm波长激发时,光纤显示出强的中红外发光.这些优异性能表明该玻璃光纤有望成为一种高效的中红外激光增益材料.     

Gd3+/Ce3+对Tb3+掺杂氟氧化物玻璃发光敏化作用的影响

本文采用高温熔融法制备了Gd/Tb、Gd/Ce、Gd/Ce/Tb掺杂的SiO₂-B₂O₃-BaF₂组分氟氧化物玻璃,通过测试X射线衍射光谱确定了其物相,通过测试其不同波段激发下的荧光光谱研究了不同Gd₂O₃掺量下Tb³⁺的发光性能,并确定了Gd₂O₃更精确的最佳掺量范围。此外,文中通过改变气氛制备了Gd/Ce/Tb共掺杂氟氧化物玻璃,对比研究了Gd³⁺和Ce³⁺对Tb³⁺的敏化作用。结果表明,本文所制备的氟氧化物玻璃都呈稳定的玻璃态;Gd³⁺和Ce³⁺对Tb³⁺的发光都具有敏化作用,且Gd₂O₃掺量为7%(摩尔分数,下同)时敏化效果相较于其他掺量最为显著,超出7%则造成猝灭;Ce₂O_3<...     

NaYF4∶Yb3+,Tm3+稀土掺杂上转换纳米材料的制备与条件优化

利用溶剂热法制备油相NaYF₄∶Yb³⁺,Tm³⁺,经“超声去油”后得到水相NaYF₄∶Yb³⁺,Tm³⁺,并对稀土离子掺杂比例、反应温度、反应时间和油酸体积分数进行条件优化，通过X-射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)和分子荧光光谱仪(MFS)对其进行表征。结果表明，当稀土离子掺杂比例为NaYF₄∶25%Yb³⁺,0.3%Tm³⁺,反应时间为60 min,反应温度为300℃,油酸体积分数为20.6%时，合成的水相NaYF₄∶Yb³⁺,Tm³⁺为六方晶型结构，六边形两平面间的平均粒径大小约为50 nm,形貌均匀、尺寸均一、分散性良好，980 nm近红外光激发下，在452和478 nm处荧光强度最大，且发出明亮的蓝色荧光。水相NaYF₄∶Yb³⁺,Tm...     

Tm3+/Ho3+共掺硫系玻璃光纤放大器增益特性

中红外2.0～3.5μm 波段激光在医疗、空气污染监测和军事等领域有着重要的应用前景。采用真空熔融淬冷法制备了 Tm3+/Ho3+共掺的Ge20Ga5Sb10S65硫系玻璃,测试了样品的吸收光谱以及800 nm激光泵浦下的荧光光谱,通过Judd–Ofelt和Mc-Cumber理论计算了Tm3+/Ho3+的辐射寿命、自发辐射几率和受激发射截面等光谱参数。在此基础上,研究了双掺离子之间的能量传递和Tm3+–Ho3+的多种跃迁过程,给出了详细的4能级系统的速率方程,并结合光功率传输方程,得出Tm3+/Ho3+共掺硫系玻璃光纤放大器在2μm波段的增益特性。数值模拟结果表明：Tm3+/Ho3+共掺硫系玻璃光纤在2μm波段的增益值达27 dB,增益带宽为112 nm,最佳掺杂光纤长度L=300 cm,所需泵浦功率Pp=200 mW,可用于2μm波段宽带放大。     

高功率中红外激光传输硫化物玻璃光纤

以高纯单质为原料,通过原料提纯和玻璃熔体蒸馏的方法制备了高光学质量的As-S硫化物玻璃,采用棒管法拉制了阶跃折射率多模光纤.表征了光纤的传输损耗和高功率中红外激光传输性能,分析了光纤的激光损伤机理.结果表明:制备的纤芯直径～200?m、数值孔径～0.35的As-S玻璃光纤在2?m和4.6?m的传输损耗分别为～0.25 ...     

镍离子激活超宽带近红外发光微晶玻璃研究进展

处在六配位八面体晶体场的过渡金属镍离子(Ni²⁺)具有超宽带近红外发光特性,其荧光半高宽是传统稀土离子(如Pr³⁺、Er³⁺)的6～8倍。Ni²⁺激活的近红外增益材料有望应用于宽带光放大器和可调谐激光器,引发了中国内外广泛关注。Ni²⁺掺杂晶体具有极高的发光效率,但晶体存在制备工艺复杂、机械加工困难和难以成纤等问题,限制了此类材料在光纤放大器和激光器领域的应用。玻璃具有易加工和成纤的优点,但Ni²⁺在玻璃中缺少合适的晶体场(配位场)环境,无法产生高效近红外发光。通过对玻璃进行热处理,可以在玻璃内部原位生成出不同类型的纳米晶体,即获得纳米晶体复合的微晶玻璃,可以为Ni²⁺提供必需的晶体场。同时,控制玻璃内部生长的晶粒尺寸,使其远小于可见光波长(如小于30nm),可有效减弱瑞利散射,使微晶玻璃具有较低的光学损耗,满足光子器件实际应用要求。讨论了Ni²⁺激活微晶玻璃的发光机理以及Ni²⁺激活晶体、...     

玻璃网络结构对CsPbI3钙钛矿量子点玻璃光学性质的影响

采用高温熔融-热处理技术,以Cs₂O、PbI₂和NaI为CsPbI₃量子点前驱体,制备了CsPbI₃量子点掺杂硼硅酸盐玻璃。X射线衍射和透射电镜观察表明,在玻璃内部析出了CsPbI₃量子点。随热处理温度上升或B₂O₃含量的增加,发光峰和吸收边出现红移,荧光强度和量子产率先增大后减小,量子点的荧光衰减寿命逐渐增长。进一步分析表明,随着B₂O₃含量增大,玻璃中二维（2D）网络结构增多,Cs⁺、Pb²⁺和I^-移动能力增强,有利于CsPbI₃量子点析出和表面缺陷钝化。CsPbI₃量子点掺杂硼硅酸盐玻璃的可调谐红光发射,在可见波段激光器和白光LED等领域具有潜在应用。     

Nb2O5对Nd3+掺杂锗酸盐玻璃光谱性能的影响

蓝光激光器在彩色激光显示、高密度光储存、海洋资源探测、水下通信以及生物科技等领域具有广泛的应用前景。目前较为成熟的Yb³⁺掺杂光纤激光器倍频后仅能获得~490 nm蓝绿光,因此如何得到接近450 nm的纯蓝光激光器是目前急需解决的问题。Nd³⁺:⁴F_3/2→⁴I_9/2能级跃迁产生的0.9 μm光经倍频后可获得~450 nm光,并可应用于蓝光激光器,但该跃迁产生的光所占荧光分支比较低。本文系统研究了1%(质量分数)Nd₂O₃掺杂50GeO₂-(20-x)PbO-15BaO-15ZnO-xNb₂O₅(x%=0%,2.5%,5%,10%,15%,摩尔分数)玻璃的吸收光谱、荧光光谱和荧光寿命,计算了相应的Judd-Ofelt强度参数以及增益带宽。研究发现,Nb₂O₅的加入会使Nd³⁺在900 nm荧光峰的吸收截面、发射截面、有效线宽和荧光分支比增加。当Nb₂O₅浓度为10%(摩尔分数)时,Judd-Ofelt强度参数Ω₂=5.91×10^-20 cm²,光谱质量参数χ=1.01,荧光分支比为42.9%。综上所述,Nb₂O₅能提高Nd³⁺ 0.9 μm的荧光分支比,从而倍频获得纯蓝光(450 nm),有利于蓝光激光器的发展及应用。     

中红外碲酸盐玻璃及光纤研究进展

近/中红外激光和超连续光源在红外光电对抗、生物医疗、遥测感知和激光探测及测距(LIDAR)等领域具有十分重要的应用价值。近年来,基于软玻璃光纤来产生和传输高亮度近/中红外(特别是2～5μm)激光方面的研究取得了显著进展。在中红外软玻璃基质中,具有相对较低声子能的碲酸盐玻璃对于设计近红外和中红外激光器和放大器、高功率中红外激光传输和传感应用无源光纤具有特别的吸引力。本文重点总结了低损耗碲酸盐玻璃的关键制备技术,并综述了碲酸盐玻璃及光纤在稀土掺杂中红外发光方面的研究进展,最后对碲酸盐玻璃及光纤应用存在的问题和发展趋势进行了总结和展望。     

稀土离子掺杂的多组分玻璃光纤

稀土离子掺杂的多组分玻璃光纤在宽带光纤放大器与上转换光纤激光器中具有重要的应用。本文介绍了稀土离子掺杂多组分玻璃光纤宽带光纤放大器与上转换光纤激光器的工作机理,综述了其最新相关研究进展,并对目前研究中需进一步解决的问题及未来的发展提出了建议与展望。从当前的研究现状来看,碲酸盐玻璃和铋基玻璃应是今后宽带玻璃光纤放大器光纤基质材料的研究重点。对上转换光纤激光器基质材料而言,如何获得更好的具有低声子能量和优良物化性能的玻璃基质,还需进一步探索。     

Tellurite Glasses for Broadband Amplifiers and Integrated Optics

The present investigation discusses the advantage of using RE-ion-doped (Nd³⁺, Tm³⁺, and Er³⁺) TeO₂ glasses for developing fiber and planar broadband amplifiers and lasers. The spectroscopy of RE-ion-doped fibers and glasses is discussed along with the thermal properties of glass hosts. The results of emission from the ³H₄ level in single-mode Tm³⁺-doped tellurite fiber show that the emission band overlaps with Er³⁺ emission from the ⁴I_13/2 level and Nd³⁺ emission from the ⁴F_3/2 level in silicate and tellurite glasses, thereby enabling the development of amplifiers and lasers between 1350 and 1650 nm. Recent results using Z-scan measurements of nonlinear refractive index and absorption demonstrate that the third-order nonlinearity in undoped TeO₂ glasses is of the order of 2 × 10⁻¹⁵ to 3 × 10⁻¹⁵ cm²·W⁻¹ between 1300 and 1550 nm. These results are briefly discussed in view of an amplifier operation combined with ultrafast all-optical switching.     

Use of CsCl to Enhance the Glass Stability Range of Tellurite Glasses for Er3+-Doped Optical Fiber Drawing

Tellurite glasses are important as a host of Er³⁺ ions because of their good solubility and because they present broadband optical gain compared with Er³⁺-doped silica, with the potential to increase the bandwidth of communication systems. However, the small glass stability range (GSR) of tellurite glasses compromises the quality of the optical fibers. We show that the addition of CsCl to tellurite glasses can increase their GSR, making it easier to draw good-quality optical fibers. CsCl acts like a network modifier in glass systems, weakening the network by forming Te–Cl bonds. We show that the thermal expansion coefficient mismatch is in the right direction for optical fiber fabrication purposes and that the Bi₂O₃ content can be used to control the refractive index of clad and core glasses. Single-mode and multi-mode Er³⁺-doped optical fibers were produced by the rod-in-tube method using highly homogeneous TeO₂–ZnO–Li₂O–Bi₂O₃–CsCl glasses.     

La2O3-Al2O3-SiO2 Glasses for High-Power, Yb3+-Doped, 980-nm Fiber Lasers

Single-mode semiconductor pumps have failed to keep pace with the increasing power requirements of Er-doped fiber amplifiers (EDFAs), so there is a need for high-powered 980-nm sources. Yb³⁺-doped tapered fiber lasers can provide high-power output by conversion of a low-brightness, high-powered, 920-nm, multimode broad stripe laser diode to a high-brightness, 980-nm, single-mode output. The tapered fiber laser requires a fiber with high numerical aperture (NA) (>0.4), a rectangular core, and good Yb³⁺ spectroscopy for efficient operation. CVD-based fiber fabrication methods are incapable of delivering fibers with an NA > ∼0.3 or with good efficiency at 980 nm so a new method of high-NA fiber fabrication was developed. The core glass composition is critical for maintaining a high-NA fiber with good power extraction while avoiding phase separation, loss, and clustering. The SiO₂ level controlled the NA and interdiffusion between core and clad, while the Al₂O₃/La₂O₃ ratio controlled phase separation. A La₂O₃-Al₂O₃-SiO₂ glass was developed that is compatible with a pure SiO₂ cladding glass and has a laser slope efficiency of 70% at 980 nm. The optimized fiber composition yielded 450 mW of 980-nm power in a single-mode fiber.     

Emission Analysis of Pr3 +& Tm3 +: B2O3-BaO-LiF/AlF3 Glasses

We report here on the preparation and emission properties of Pr³⁺(4f²) and Tm³⁺ (4f¹²) ions doped in newly developed to transparent glassy matrices of BBLi (= B₂O₃-BaO-LiF) BBAl (= B₂O₃-BaO-AlF₃). Under an UV source (355 nm), both the Tm³⁺: BBLi and Tm^{3 +}: BBAl glasses have shown bright blue emission at 452 nm. With regard to both the Pr³⁺: BBL and Pr³⁺: BBAl glasses red emission have been noticed upon excitation with blue excitation wavelength (445 nm).These results have also been obtained from the measurement of their emission spectra. For such emission bands, decay curves have been recorded to obtain their lifetimes. We have prepared optical glasses with good transparency and stability. From the measurement of XRD spectra, amorphous nature of these glasses have been confirmed. Between the two glasses studied, glass containing Li has demonstrated an extended UV transmission and also it has revealed an improved NIR transmission ability compared to the other glass with LiF.     

Eu2+-Doped Glass Ceramics Containing BaF2 Nanocrystals as a Potential Blue Phosphor for UV-LED

The Eu²⁺-doped glass ceramics containing BaF₂ nanocrystals were prepared and their luminescence properties were investigated. The excitation spectra of Eu²⁺-doped glass ceramics showed an excellent overlap with the main emission region of an ultraviolet light-emitting diode (UV-LED) centered at 380 nm. The 450 nm emission of Eu²⁺ in glass ceramics under the 385 nm excitation was much stronger than that in glass. The Eu²⁺-doped glass ceramics containing BaF₂ nanocrystals may be used as a potential blue-emitting phosphor for UV-LED.     

基于脉冲喷射技术的硫系玻璃光纤制备方法探索

硫系玻璃光纤因具有独特的红外光学特性,在红外成像、激光传输和传感等诸多领域具有广阔的应用前景。目前,硫系玻璃光纤的拉制方法主要包括双坩埚法和预制棒拉制法。其中,双坩埚法装置复杂,预制棒拉制法需要提前制备高质量的预制棒。此外,这两种方法均要求玻璃具有较高的抗析晶能力,限制了硫系玻璃光纤新材料的开发。本工作创新性地将脉冲喷射技术引入到硫系玻璃光纤制备领域,通过硫系玻璃光纤纤芯的拉制,探索该方法在玻璃光纤制备上的可行性。通过对玻璃熔体施加持续性的脉冲扰动,坩埚底部小孔处能产生连续的射流,并且在下落过程中发生凝固,从而获得玻璃纤芯。采用该方法,成功制备了一种组成为Ge₂₈Sb₁₂Se₆₀的玻璃光纤纤芯。脉冲喷射法具有装置简单、操作容易等优点,通过连续且规律的脉冲和坩埚内外压力差实现硫系玻璃光纤的拉制,与传统依靠重力拉制的方法相比,脉冲喷射法具有更为丰富的调控手段,从而为新型硫系玻璃光纤的制备提供参考。     

Surface modification and fabrication of white-light-emitting Tm3+/CdS quantum dots co-doped glass fibers

Due to the widely tunable band gap and broadband excitation, CdS quantum dots (QDs) show great promise for yellow-light luminescence center in white-light-emitting devices. The light intensity of the CdS QD-doped glass was enhanced by doping the Tm³⁺ ions due to the higher absorption rate. The influence of Tm³⁺ ions on the surface structure of CdS QDs was enormous according to the first-principles calculations. Doping Tm³⁺ ions change the surface state of CdS QDs, which will fix the QDs emission peaks and enhance the luminescence of CdS QDs at a lower heat-treatment temperature. White-light emission was obtained by tuning the relative concentration between Tm³⁺/CdS QDs. However, there is a fundamental challenge to fabricate QD-doped glass fibers by rod-in-tube method since uncontrollable QDs crystallization is hard to avoid. Herein, a white-light-emitting borosilicate glass fiber was fabricated by the “melt-in-tube” method using a special designed Tm³⁺/CdS QDs co-doped borosilicate glass with low-melting temperature as fiber core. After heat treatment, ideal white-light emission was observed from the fiber under excitation at single wavelength (359 nm). This finding indicates that Tm³⁺/CdS QDs co-doped glass fiber with white-light-emitting devices has potential application as gain medium of white-light-emitting sources and fiber lasers.