可用紫外光照明调谐激光

纽约市大学王后学院、福德汉大学和国立莫斯科大学的科学家，将掺染料的向列液晶放在两片玻璃之间，做成一种激光器，可用紫外光照明进行调谐。该组发现，在低辐照水平时，以Nd：YAG激光抽运的掺染料向列液晶的激射波长移动15～20BE。在紫外辐射断开以后，激光波长又回到原来的620nm左右。激射波长的可逆调谐，为新的手征偶氮染料异构设计可用光调谐的线性与非线性光学器件开辟了新的可能性。     

基于激光瞬态特性的内腔气体浓度光纤传感器

报道了一种基于掺铒光纤激光器瞬态特性的内腔吸收式气体浓度传感器.介绍了掺铒光纤激光器内腔吸收谱的基本原理,以及激光激射延迟时间与气体浓度的关系.用光纤环全反镜和光纤Bragg光栅构成F-P线形腔,通过调节光栅的反射波长,使激光激射波长落在乙炔的一个较强的吸收峰1532.83 nm上.通过测量激光激射延迟时间可以获得气体的浓度.实验证实了方案的可行性,该装置的灵敏度可以达到10×10~(-6).     

掺钕无机惰性液体激光技术研究

为了研究掺钕无机惰性液体的配制、光谱和激光特性,采用实验研究的方法,在实验室制备了无机惰性液体激光增益介质Nd-POCl3-SnO2,测试了其抽运吸收和荧光特性;采用氙灯抽运和行波放大的方法实验研究了该液体的增益特性,并进行了初步的自由振荡出光实验。得到了性质稳定的掺钕无机惰性液体,利用该液体作为增益介质的放大器获得了1%/cm的增益系数,激光器实验则获得了中心波长为1051nm、脉宽为83.33μs的自由振荡激光输出。结果表明,掺钕无机惰性液体的配制的必要措施是干燥条件的保证,同时Lewis酸和掺钕浓度对于液体的荧光寿命也起到限制作用,该液体增益介质的光谱特性接近激光钕玻璃,单脉冲工作条件下可以得到稳定的激光输出。     

运用波长与光纤长度关系选择激光波长

推导了掺Yb 光纤激光器中激射波长与掺杂光纤长度、掺杂浓度等的关系式。依据所得到的关系式,在981.5 nm 半导体激光抽运的掺Yb 环形腔石英光纤激光器中,获得了中心波长在1053nm 的激光输出。光抽运阈值功率为1.85 m W。激光半功率宽度(FWHM)为5 nm ,输出功率为104μW,斜率效率为3% 。激光空间模式为基横模。     

固体激光与铜蒸气激光混合抽运的染料激光放大实验

采用倍频Nd:YAG绿光激光器与铜蒸气激光器混合抽运双级染料激光放大器的实验方法,通过抽运激光器精确的脉冲同步控制和匹配技术,获得了9.0W的染料激光输出,第二级染料激光放大器对抽运激光的提取效率达到了26.6%,系统总提取效率达到了13.6%.实验研究了染料激光输出功率和抽运激光提取效率随染料激光波长的变化关系.     

微碟激光器的单模低阈值激射

简单分析了碟型微腔激光器中的激射模式及自发发射系数。采用反应离子刻蚀和选择性刻蚀方法蚀刻出InGaAs InGaAsP多量子阱 (MQW)碟型激光器 ,碟直径 3 μm ,在液氮温度下进行光抽运实验 ,观察其模式特性。实现了单模激射 ,波长 1 5 μm ,抽运阈值 18μW。     

倍频固体激光抽运双级染料激光放大系统的实验

报道了用倍频Nd∶YAG绿光激光器抽运双级染料激光放大系统的实验过程。实验应用两台高平均输出功率、高脉冲重复频率的倍频Nd∶YAG绿光激光器,通过精确的脉冲同步控制技术,实现了对双级染料激光放大系统的抽运,获得了放大级最高提取效率16. 8% ,总提取效率10. 6% ,最高输出功率9. 2W的实验结果。得到了抽运激光提取效率随染料激光波长、染料溶液浓度和抽运激光峰值功率的变化关系。     

甲酚紫连续波染料激光器获得近40毫瓦输出

有机染料激光器是一种重要的可调谐相干光源。它以荧光染料作为工作物质,用闪光灯、氮分子激光器、倍频的钇铝石榴石激光器、准分子激光器、铜蒸汽激光器、较高功率的氩或氪离子激光器作泵浦源。染料产生的荧光波长比泵浦波长稍长一些(称为斯托克斯位移),当满足一定的物理条件后,这种荧光就能转变为激光。其激光作用可以出现在强荧光的任何波长上。由于染料的荧光谱带很宽,因此染料激光作用的可能范围也很宽。只要我们适当地选择几种染料,并采用某些调谐元件,就可以使激光波长在宽广的光     

发射蓝光的光泵InGaN垂直腔面发射激光器

在１９９９年５月举行的激光电光学会议（巴尔的摩）的逾期论文中,日本东京大学和德国维尔兹堡大学的研究人员报导了室温下从光泵垂直腔面发射激光器（ＶＣＳＥＬ）二维列阵中获得蓝光发射（３９９ｎｍ波长）的成果。这种器件的列阵可望大大降低高密度光学存储器的读出时间。列阵中每一柱形氮化铟镓垂直腔面发射激光器的直径为１８μｍ,器件的间距为２２μｍ。这种激光器用氮激光抽运的３Ｈｚ重复频率染料激光器的３６７ｎｍ波长抽运,激光器的阈值抽运能量为１０ｍＪ／ｃｍ２或片载流子密度为２～４×１０１２ｃｍ２。该器件以多层结构形…     

输出功率50 W的脉冲染料激光放大器

推导了准稳态下横向抽运的脉冲染料激光放大器的简化速率方程,提出了双侧横向抽运方式的脉冲染料激光放大器的设计原则和设计方法.应用高功率脉冲染料激光放大器的物理设计结果,研制了输出功率为50 W的脉冲染料激光放大器的实验装置.采用铜蒸气激光(CVL)作为抽运光,在此染料激光放大器上进行了实验研究,获得染料激光输出功率为52 W,抽运激光功率提取效率为41%.给出了染料激光波长、注入染料激光功率以及抽运激光的时间和空间匹配特性与染料激光放大器输出激光功率和抽运激光功率提取效率的相互关系,讨论了染料溶液浓度对双侧横向抽运方式的脉冲染料激光放大器的输出光束质量的影响.     

Near-infrared distributed feedback laser emission based on cascade Förster resonance energy transfer to Nile Blue aggregates

We present the real time tunable distributed feedback lasing in the region of near-infrared light obtained in a dye doped polymeric layer via cascade energy transfer based on Förster resonance (FRET). The Rhodamine 6G and Rhodamine B laser dyes were used as a donor for FRET effect, while the Nile Blue dye served as an acceptor. The shift of the emission from visible to near-infrared region was possible due to the formation of the dyes aggregates of lower than for molecules energy levels. Therefore, through the sequence of energy transfers between molecules and aggregates, the shift between excitation and stimulated emission spectra of about 200 nm can be achieved. The use of the periodically modulated pumping beam from pulsed Nd:YAG laser allows to select and amplify particular wavelength from the gain profile according to Bragg conditions, what can be easily tuned by changing the period of the interference pattern. The reported tunability of distributed feedback emission from 725 nm to 745 nm confirmed that only Nile Blue aggregates were involved in the laser action, while donor molecules and aggregates, as well as acceptor in non-aggregated form, acted as a canal for energy transfer.     

Collagen network as the scaffold for spontaneously distributed optical resonators

The idea behind this work was to acquire one dimensional lasing in the Rhodamine 6G dye doped collagen fibers with the control of random lasing phenomenon properties by changing the dye molecular arrangement. We show that a simple manipulation of the dye concentration in biopolymeric fibril matrix bulk and an additional use of α-cyclodextrin (α-CD) molecules determine formation of specific dye aggregates and as a consequence the shift of the random lasing emission wavelength in the desired direction. The analysis of the light transport mean free path in function of the dye and (α-CD) concentration was done with the use of coherent back scattering technique.     

温度对强激光泵浦下激光染料荧光性能的影响

对三种在染料激光器中常用的激光染料(若丹明6G、硫化若丹明B、若丹明101)的乙醇溶液在强激光泵浦下的荧光性能进行了实验研究.测量了荧光强度在不同溶液浓度、不同温度下的变化规律.发现了温度对染料的最佳浓度值有一定影响:随着温度的降低,硫化若丹明B和若丹明101的最佳浓度值减小,而若丹明6G的最佳浓度值不随溶液温度变化.     

激光二极管双端抽运Tm:YLF 1.9 μm激光器

报道了一种激光二极管(LD)双末端抽运Tm:YLF激光器,在1.9 μm处获得了连续波(CW)输出。1.9 μm激光可用于抽运Ho晶体获得2 μm激光。在理论上,分析了掺Tm3+激光器的运转机制和能量转换损耗,计算出Tm:YLF激光器在理论上的斜率效率达到50%。在实验上,抽运源使用工作波长为792 nm的光纤耦合激光二极管,抽运光均分为两束双端抽运Tm:YLF晶体,两块晶体串接在折叠腔内。Tm:YLF 晶体的掺杂原子数分数为4%, 尺寸为3 mm×3 mm×12 mm。测量了输出镜在不同透射率情况下激光器的输出激光波长,当输出镜透射率T=26%时,在1.9μm处获得20.1 W的连续波激光输出,相应的抽运功率为75 W,阈值抽运功率为9 W,斜率效率为34%,光-光转换效率为27%。     

Near-IR dye laser for diode-pumped operation

A dye laser pumped by AlGaInP laser diodes produced efficient, low threshold operation at wavelengths between 740 and 800 nm. Rhodamine 700, oxazine 750, DOTCI and oxazine 1 dyes were demonstrated. Optical conversion efficiencies approaching 50% and output power as high as 361 mW were obtained when pumping with a DCM-based dye laser. Parametric variations of the pump power and wavelength were performed over the range of 615 nm to 690 nm to provide a more complete characterization of the dye laser     

850 nm有源区无铝高功率SCH-SQW激光器

设计并制作了条宽 10 0 μm ,腔长 1mm的有源区无铝高功率SCH SQW激光器 ,室温连续输出功率达 1W ,阈值电流密度为 46 0A/cm2 ,外微分量子效率为 0 6 8W/A ,激射波长为 849nm(腔面未镀膜 )。     

Starch: Application of biopolymer in random lasing

Here we report on the possible application of starch as a dye-doped biopolymeric matrix designed for random lasing generation. Gelatinized biopolymer doped with Rhodamine 6G was used as light amplification medium as well as source of positive feedback which is originating from high surface roughness fluctuations. It is demonstrated that, applying the starch as a matrix for laser dye we can significantly increase photostability of laser emission with respect to other biopolymeric based systems which is great advantage of this material.     

激射波长和泵浦波长对掺Yb~(3+)双包层光纤激光器的影响

为探讨激射波长和泵浦波长对掺Yb3+双包层光纤激光器的影响,数值模拟了泵浦波长为975nm和915nm,激射波长在1050nm至1120nm范围变化时,掺Yb3+双包层光纤激光器的输出特性.结果表明,当泵浦波长为975nm,激射波长在1088nm左右,以及泵浦波长为915nm时,激射波长在1080nm左右时,双向泵浦和反向泵浦的掺Yb3+双包层光纤激光器输出功率达到最大值.与915nm的泵浦源相比,利用975nm泵浦可使泵浦阈值功率降低以及获得更高的激光翰出功率.泵浦波长为975nm和915nm时,激射波长在1090nm附近,阈值功率达到最低值.所得的结果对激光器的优化设计具有重要意义.     

Dye-doped step-index polymer optical fiber for broadband opticalamplification

We report the development of a novel and simple technique for fabricating polymer optical fibers of good optical quality for special device applications. This technique aims at polymer fibers doped with various functional organic materials. On the basis of the technique, step-index polymer optical fibers doped with laser dyes have been fabricated. High-gain and high-efficiency optical amplification has been achieved in a Rhodamine B-doped polymer fiber with a low pump power of less 1 kW and pulse width 5 ns. Because a high dye concentration is used, the optimal wavelength range of optical amplification in this fiber is significantly red-shifted toward the center of the communication window (at 650 nm wavelength) of methyl methacrylate-based polymer optical fiber. The shift is from the originally 560 and 590 nm to presently 610 to 640 nm. We also present experimental results that show good photostability of the Rhodamine B-doped polymer fiber, compared with those recently reported in the improved polymer material systems. From the experimental observation, we identified the thermally induced bleach of dye molecules as the major contributing factor to the lifetime of our material system     

一种新型皮秒脉冲激光器

一种新型皮秒脉冲激光器由序列脉冲激光的产生、单脉冲激光的选取、放大和倍频等部分组成,激光器工作物质选用Nd∶YAG晶体,用两个格兰棱镜分别作为起偏器和检偏器,激光器的振荡级利用被动锁模染料产生的锁模序列脉冲激光,经过单脉冲选择器选取出其中的一个单脉冲激光,再经激光器放大部分的放大和倍频晶体的倍频后,激光器最终输出能量为120mJ,脉冲宽度为100ps,波长为532nm的单脉冲激光,其功率约为1.2×109W,功率密度约为4.2×109W/cm2,系统的外触发同步精度优于2μs。