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Conditions for efficient build-up of power in a ring-cavity with Rh:BaTiO3 Rh:BaTiO3在环形腔中有效积累功率的条件
Pub Date : 1998-01-01 DOI: 10.1364/cleo_europe.1998.cfk5
M. Kaczmarek, R. Eason
Numerous interaction geometries have been developed for photorefractive materials that rely on amplification of light via the two-beam coupling effect. One of the most elegant and simple configurations is a unidirectional ring resonator, which consists of a photorefractive crystal placed in a ring cavity and pumped by an external beam [1]. If the two-beam coupling gain is above threshold, the resonating beam will build up from the amplification of scattered light.
许多相互作用几何已经发展为光折变材料,依赖于光的放大通过双光束耦合效应。最优雅和简单的配置之一是单向环形谐振器,它由放置在环形腔中的光折变晶体组成,并由外部光束泵浦[1]。当双光束耦合增益大于阈值时,散射光的放大会产生共振光束。
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引用次数: 0
80 μm Wide InAlGaAs Laser Diodes with 44 % Wallplug Efficiency at 7 W cw Output Power 80 μm宽的InAlGaAs激光二极管,在7w连续输出功率下,壁塞效率为44%
Pub Date : 1998-01-01 DOI: 10.1364/cleo_europe.1998.cthg3
A. Schmitt, M. Mikulla, P. Chazan, M. Walther, R. Kiefer, J. Braunstein, G. Weimann
For high power laser diodes, a high wallplug efficiency is a key-requirement for improved reliability at elevated output power levels. We report on MBE-grown high-power InAIGaAs-laser diodes with a wallplug efficiency of 44 % at an output power of more than 7 W cw.
对于高功率激光二极管,在高输出功率水平下,高壁塞效率是提高可靠性的关键要求。我们报道了mbe生长的高功率inaigaas激光二极管,其壁塞效率为44%,输出功率超过7w cw。
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引用次数: 0
New Frequency Conversion Effects in HIO3 and α-LiIO3 Single Crystals Showing high χ(2) and χ(3) Nonlinear Susceptibilities 具有高χ(2)和χ(3)非线性磁化率的HIO3和α-LiIO3单晶中的新变频效应
Pub Date : 1998-01-01 DOI: 10.1364/cleo_europe.1998.cthh29
A. Kaminskii, A. Butashin, J. Hulliger, P. Egger, P. Mikhail, H. Eichler, J. Findeisen, A. Lyashenko
We report on first experimental observations of new manifestations of nonlinear optical interactions under one micron picosecond excitation in acentric HIO3 and α-LiIO3 single crystals, which offer simultaneously high χ(2) and χ(3) nonlinear effects.
本文报道了在1微米皮秒激发下,非中心HIO3和α-LiIO3单晶中非线性光学相互作用新表现的首次实验观察,这些单晶同时提供高χ(2)和χ(3)非线性效应。
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引用次数: 0
RF-Excited Slab Waveguide CO2 Lasers Utilising Graded Phase Mirror Resonators 利用梯度相镜谐振器的射频激发平板波导CO2激光器
Pub Date : 1998-01-01 DOI: 10.1364/cleo_europe.1998.cwn2
B. Wasilewski, H. Baker, D. Hall
RF discharge excited slab-waveguide carbon dioxide lasers have been developed as relatively inexpensive sources of good beam quality, high power, far infrared radiation (10.6µm). They commonly incorporate a hybrid resonator design which involves waveguide propagation in the transverse direction and a confocal-unstable design in the lateral (wide) dimension. Such resonators offer excellent beam quality, adequate for most applications. However, they may exhibit variations in the beam shape when mirrors are tilted, and scaling the laser to high powers requires use of wide spherical mirrors, which causes increased sensitivity to unwanted spherical curvatures (bending and twisting) overlaid on the mirror shape during manufacturing and/or mounting, To remove this unwanted behaviour, alternative resonator geometries are under consideration.
射频放电激发板波导二氧化碳激光器作为光束质量好、功率高、远红外辐射(10.6µm)的相对廉价的光源已经得到了发展。它们通常采用混合谐振器设计,其中包括横向波导传播和横向(宽)尺寸的共焦不稳定设计。这种谐振器提供优秀的光束质量,足以满足大多数应用。然而,当反射镜倾斜时,它们可能会表现出光束形状的变化,并且将激光缩放到高功率需要使用宽球面反射镜,这会导致在制造和/或安装期间对覆盖在反射镜形状上的不需要的球面曲率(弯曲和扭曲)的灵敏度增加。为了消除这种不需要的行为,正在考虑替代谐振器几何形状。
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引用次数: 0
Stable picosecond pulse generation at 1.3 μm in a Pr3+-doped all-fiber laser actively mode-locked using a novel fiber-optic phase modulator 利用一种新型光纤相位调制器,在1.3 μm的Pr3+掺杂全光纤激光器中产生稳定的皮秒脉冲
Pub Date : 1998-01-01 DOI: 10.1364/cleo_europe.1998.ctuf4
T. G. Nielsen, W. Hodel, H. Weber, D. Costantini, A. Iocco, N. H. Ky, H. Limberger, R. Salathé, G. Fox
Rare-earth doped fibers are ideal candidates for the realization of simple, compact sources of ultrashort pulses. Considerable effort has been devoted to obtain short pulse generation in Er3+-doped fiber lasers at 1.55 μm. In contrast, little work has been done on Pr3+-doped fiber lasers emitting in the important 1.3 μm region where there is still a lack of compact, tunable short pulse sources. In this work we report on a all-fiber laser incorporating a Pr3+-doped active fiber, fiber Bragg gratings (FBG’s) as cavity mirrors, and a novel piezoelectric fiber-optic phase modulator (PFOM) for active mode-locking [1]. The experimental set-up is schematically shown in the following Figure.
稀土掺杂光纤是实现简单、紧凑的超短脉冲源的理想候选材料。在1.55 μm的掺Er3+光纤激光器中实现短脉冲产生已经付出了大量的努力。相比之下,在重要的1.3 μm区域内发射Pr3+的光纤激光器的研究工作很少,因为该区域仍然缺乏紧凑的、可调谐的短脉冲源。在这项工作中,我们报道了一种全光纤激光器,其中包括Pr3+掺杂的有源光纤,光纤布拉格光栅(FBG)作为腔镜,以及一种用于有源锁模的新型压电光纤相位调制器(PFOM)[1]。实验装置示意图如下图所示。
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引用次数: 1
Spectroscopic characterization and diode-pumped laser action at 2.7μm of Er:Lu2O3 光谱表征和二极管泵浦激光作用在2.7μm Er:Lu2O3
Pub Date : 1998-01-01 DOI: 10.1364/cleo_europe.1998.cff10
V. Peters, L. Fornasiero, E. Mix, A. Diening, K. Petermann, G. Huber
The sesquioxide Lu2O3 (Lutetia) is isostructural to the comparatively well examined Y2O3 (Yttria). Therefore the thermal conductivity of Lutetia is assumed to be in the same high range as in Yttria (27 W/mK [1]), which makes Lutetia an interesting host material for high power lasing. Due to its high melting point (around 2500°C) is was impossible to grow Lutetia from crucibles in the past so that size and optical quality of existing samples were limited. We have, for the first time to our knowledge, grown Lutetia doped with RE3+-ions from rhenium crucibles using the Nacken-Kyropoulos technique. First samples show monocrystalline regions with rather low stress induced birefringence.
倍半氧化物Lu2O3 (Lutetia)与相对较好的Y2O3 (ytriia)是同结构的。因此,假定黄体的热导率与钇的热导率处于相同的高范围(27 W/mK[1]),这使黄体成为高功率激光的有趣宿主材料。由于其高熔点(约2500°C),过去不可能从坩埚中生长黄体,因此现有样品的尺寸和光学质量受到限制。据我们所知,我们第一次用Nacken-Kyropoulos技术从铼坩埚中获得了掺杂RE3+离子的Lutetia。第一个样品显示单晶区域具有较低的应力诱导双折射。
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引用次数: 4
All-optical pseudorandom bit sequence generator 全光伪随机位序列发生器
Pub Date : 1998-01-01 DOI: 10.1364/cleo_europe.1998.cpd2.2
A. Poustie, K. Blow, R. Manning, A. Kelly
The ability to perform all-optical digital information processing is one of the key requirements for future photonic networks. Recently, the use of semiconductor optical amplifier based all-optical interferometric switches [1] has allowed practical demonstrations of advanced functionality to be demonstrated. These have included a bit-serial regenerative optical memory which is capable of long term storage [2] and has the ability to restore the optical logic level [3]. Here we describe a further advance in all-optical digital functionality with a demonstration of an all-optical pseudorandom bit sequence (PRBS) generator. The all-optical PRBS comprises two coupled regenerative memories [2] which act as a time-of-flight shift register for optical pulses. A digital PRBS can be generated by applying the logical XOR function between the output of the register and a tap point and feeding the logical result back into the start of the register [4]. We use two TOAD all-optical switching gates [5] to create the all-optical PRBS architecture. One TOAD is used for the XOR function and the other acts as a wavelength converter and all-optical regenerator. The PRBS output depends on the number of pulses m in the shift register and the tap position n (n
能够进行全光数字信息处理是未来光子网络的关键要求之一。最近,使用基于半导体光放大器的全光干涉开关[1],可以演示先进功能的实际演示。其中包括一个位串行再生光存储器,它能够长期存储[2],并具有恢复光逻辑电平的能力[3]。在这里,我们通过演示全光伪随机比特序列(PRBS)发生器来描述全光数字功能的进一步发展。全光PRBS包括两个耦合再生存储器[2],作为光脉冲的飞行时间移位寄存器。数字PRBS可以通过在寄存器的输出和抽头点之间应用逻辑异或函数并将逻辑结果反馈到寄存器的开始处来生成[4]。我们使用两个TOAD全光开关门[5]来创建全光PRBS架构。一个TOAD用于异或功能,另一个作为波长转换器和全光再生器。PRBS输出取决于移位寄存器中的脉冲数m和分接位置n (n
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引用次数: 1
Comparison of weld quality with normal and 30° incident laser beams 正常入射和30°入射激光束焊缝质量的比较
Pub Date : 1998-01-01 DOI: 10.1364/cleo_europe.1998.cthh96
E. Ng, I. Watson
The thermal cycle during laser welding of high carbon steels typically has a rapid cooling rate of about 104 K/s; in high carbon steels this results in a microstructure comprising ferrite matrix and hard martensite colonies [1,2]. Such high cooling rates can lead to deterioration of the weld quality due to hardness discontinuities between the fusion and heat affected zones. The hardness induced in the welded joint is dependent on the cooling process, itself being dependent on the laser parameters and weld geometry. The weld quality and hardness characteristics were improved by implementing an angular welding technique; this ameliorated the poor characteristics associated with rapid cooling. Two different angles of incidence (0°,30°) for welding were compared as were effects of the pulse length and pulse repetition frequency (PRF) on the mechanical and microscopic properties of the material. The gauge plates (0.88 mm) that were welded had a nominal composition of 0.85 wt % C, 0.4 wt % Si, 1.1 wt % Mn, 0.4 wt % Cr, 0.25 wt % V and 0.4 wt % W. The welding was done with Lumonic’s MS830 Nd:YAG laser, operating at 1.06 pm. The beam was delivered via a fibre optic system which was robotically manipulated. The welds were produced with a constant power of 200 watts and an argon shielding gas pressure of 5 x 104 Pa. The effect of varying the pulse length and PRF was quantified by measuring the hardness transverse to the weld direction, tensile strength, aspect ratio, weld volume formation rate and examining the phase transformation. Figures 1 and 2 show the hardness profiles of the weld for different pulse lengths and PRF, for the flat and 30° welding configurations, respectively. For both geometries, the hardness profiles decreased with increasing pulse length and PRF, however, the hardness gradients were lower for the 30° welding configuration. The hardness profile was dependent on the thermal distribution around the fusion and heat affected zones. Because of the rapidity of cooling for the normal weld geometry, the main weld region consisted of a martensitics structure [3], and the grain structure was coarser and less dense in the fusion zone. For the 30° welding configuration, a slower cooling rate was achieved, leading to a less brittle weld. The grain structure was typically fine and granular, and the structure was completely modified at the fusion zone. Additionally, a lower aspect ratio was obtained; this was due to the wider weld width produced with this geometry. Benefits of welding at 30° include: improved microstructure and reduced peak hardness profiles, greater weld width, higher tensile strength and greater weld volume formation rate. Ultimately, a higher welding speed was achieved.
高碳钢激光焊接过程中的热循环通常具有快速冷却速度,约为104 K/s;在高碳钢中,这导致了由铁素体基体和硬马氏体集落组成的微观结构[1,2]。如此高的冷却速度会导致焊接质量的恶化,因为熔合区和热影响区之间的硬度不连续性。焊接接头中产生的硬度取决于冷却过程,其本身取决于激光参数和焊缝几何形状。采用角焊技术,提高了焊缝质量和硬度特性;这改善了与快速冷却相关的不良特性。比较了两种不同的焊接入射角(0°和30°),以及脉冲长度和脉冲重复频率(PRF)对材料力学和微观性能的影响。焊接的压力表(0.88 mm)的标称成分为0.85 wt % C, 0.4 wt % Si, 1.1 wt % Mn, 0.4 wt % Cr, 0.25 wt % V和0.4 wt % w。焊接使用Lumonic的MS830 Nd:YAG激光器,工作时间为下午1点06分。光束通过一个由机器人操纵的光纤系统传送。焊接的功率为200瓦,氩气保护压力为5 × 104 Pa。通过测量焊缝方向的横向硬度、抗拉强度、宽高比、焊缝体积形成率和观察相变来量化脉冲长度和PRF的影响。图1和图2分别显示了平焊和30°焊接配置下不同脉冲长度和PRF下焊缝的硬度分布图。对于这两种几何形状,硬度分布随着脉冲长度和PRF的增加而降低,但对于30°焊接结构,硬度梯度较低。硬度分布取决于熔合区和热影响区周围的热分布。由于正常焊缝几何形状冷却速度快,焊缝主要由马氏体组织[3]组成,熔合区晶粒组织较粗,密度较低。对于30°焊接配置,可以实现较慢的冷却速度,从而降低焊缝的脆性。晶粒组织呈典型的细粒状,在熔合区组织完全改变。此外,获得了较低的纵横比;这是由于更宽的焊缝宽度产生了这种几何形状。在30°温度下焊接的好处包括:改善微观结构,降低峰值硬度,增加焊缝宽度,提高抗拉强度和焊缝体积形成率。最终实现了更高的焊接速度。
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引用次数: 0
Laser Surface Modifications 激光表面修饰
Pub Date : 1998-01-01 DOI: 10.1364/cleo_europe.1998.cmb1
H. Hügel
Any machine parts, tools construction components and workpieces do interact via their surfaces with each other respectively with their environments. Depending on the application field and the task, the interaction occurs on the basis of mechanisms that can be of mechanical, chemical, electrical or optical nature or of several of these. In any case, the property of the surfaces is an essential feature with respect to the functionality of the particular element. In general, the requirements are met by materials that are not necessarily, at the same time well-suited for the piece in its entirety, be it for reasons of design, processing technologies, costs or others. Against this background, modern production approaches rely on a great variety of adequate and well developed surface technologies.
任何机器零件,工具,结构部件和工件都通过它们的表面相互作用,分别与它们的环境相互作用。根据应用领域和任务的不同,相互作用发生在机械、化学、电子或光学性质或其中几种性质的机制的基础上。在任何情况下,表面的性质都是与特定元素的功能相关的基本特征。一般来说,由于设计、加工技术、成本或其他原因,满足要求的材料不一定同时完全适合该件。在这种背景下,现代生产方法依赖于各种充分和发达的表面技术。
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引用次数: 0
Compact cw laser source for high-resolution spectroscopy between 6.8 and 12.5 μm 紧凑的连续波激光源,高分辨率光谱范围为6.8 ~ 12.5 μm
Pub Date : 1998-01-01 DOI: 10.1364/cleo_europe.1998.cfh6
V. Petrov, C. Rempel, K. Stolberg, W. Schade
Tunable monochromatic laser sources in the mid-infrared (MIR) spectral range are particularly important for high-sensitivity and high-resolution molecular spectroscopy. The optimum combination of frequency stability and spectral resolution can be provided only by cw laser radiation. Recently considerable progress has been achieved in developing such devices emitting above 3 μm that are based on difference-frequency generation (DFG) in AgGaS2, but the tunability of previously demonstrated all-solid-state DFG schemes was limited to a narrow region near 5 μm because of the requirement of 90° phase matching [1]. We report here substantial improvement of the tunability range using for the first time to our knowledge critical phase matching in AgGaS2 in the cw regime. The freedom with respect to the spectral position of the two pumping laser diodes allows the choice of relatively powerful pumping diodes which compensates for the reduced interaction length. This, in combination with type-II phase-matching, provides maximum output powers on the μW level and tunability between 6.8 and 12.5 μm with a single crystal as short as 1 cm.
中红外(MIR)光谱范围内的可调谐单色激光源对于高灵敏度和高分辨率分子光谱学尤为重要。只有连续波激光辐射才能提供频率稳定性和光谱分辨率的最佳组合。最近,基于AgGaS2中差频产生(DFG)的发射波长在3 μm以上的器件的开发取得了相当大的进展,但由于需要90°相位匹配,先前展示的全固态DFG方案的可调性仅限于5 μm附近的狭窄区域[1]。据我们所知,我们在此报告了在cw状态下首次使用AgGaS2的临界相位匹配来大幅改善可调性范围。相对于两个泵浦激光二极管的光谱位置的自由允许选择相对强大的泵浦二极管,这补偿了减少的相互作用长度。这与ii型相位匹配相结合,提供了μW级的最大输出功率和6.8到12.5 μm之间的调谐,单晶短至1厘米。
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引用次数: 0
期刊
Conference on Lasers and Electro-Optics Europe
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