Conference on Lasers and Electro-Optics Europe最新文献

{"title":"Conditions for efficient build-up of power in a ring-cavity with Rh:BaTiO3","authors":"M. Kaczmarek, R. Eason","doi":"10.1364/cleo_europe.1998.cfk5","DOIUrl":"https://doi.org/10.1364/cleo_europe.1998.cfk5","url":null,"abstract":"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.","PeriodicalId":10610,"journal":{"name":"Conference on Lasers and Electro-Optics Europe","volume":"109 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80665804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"80 μm Wide InAlGaAs Laser Diodes with 44 % Wallplug Efficiency at 7 W cw Output Power","authors":"A. Schmitt, M. Mikulla, P. Chazan, M. Walther, R. Kiefer, J. Braunstein, G. Weimann","doi":"10.1364/cleo_europe.1998.cthg3","DOIUrl":"https://doi.org/10.1364/cleo_europe.1998.cthg3","url":null,"abstract":"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.","PeriodicalId":10610,"journal":{"name":"Conference on Lasers and Electro-Optics Europe","volume":"56 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84873517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New Frequency Conversion Effects in HIO3 and α-LiIO3 Single Crystals Showing high χ(2) and χ(3) Nonlinear Susceptibilities","authors":"A. Kaminskii, A. Butashin, J. Hulliger, P. Egger, P. Mikhail, H. Eichler, J. Findeisen, A. Lyashenko","doi":"10.1364/cleo_europe.1998.cthh29","DOIUrl":"https://doi.org/10.1364/cleo_europe.1998.cthh29","url":null,"abstract":"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.","PeriodicalId":10610,"journal":{"name":"Conference on Lasers and Electro-Optics Europe","volume":"413 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84886392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RF-Excited Slab Waveguide CO2 Lasers Utilising Graded Phase Mirror Resonators","authors":"B. Wasilewski, H. Baker, D. Hall","doi":"10.1364/cleo_europe.1998.cwn2","DOIUrl":"https://doi.org/10.1364/cleo_europe.1998.cwn2","url":null,"abstract":"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.","PeriodicalId":10610,"journal":{"name":"Conference on Lasers and Electro-Optics Europe","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74488773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"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","authors":"T. G. Nielsen, W. Hodel, H. Weber, D. Costantini, A. Iocco, N. H. Ky, H. Limberger, R. Salathé, G. Fox","doi":"10.1364/cleo_europe.1998.ctuf4","DOIUrl":"https://doi.org/10.1364/cleo_europe.1998.ctuf4","url":null,"abstract":"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.","PeriodicalId":10610,"journal":{"name":"Conference on Lasers and Electro-Optics Europe","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73856928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectroscopic characterization and diode-pumped laser action at 2.7μm of Er:Lu2O3","authors":"V. Peters, L. Fornasiero, E. Mix, A. Diening, K. Petermann, G. Huber","doi":"10.1364/cleo_europe.1998.cff10","DOIUrl":"https://doi.org/10.1364/cleo_europe.1998.cff10","url":null,"abstract":"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.","PeriodicalId":10610,"journal":{"name":"Conference on Lasers and Electro-Optics Europe","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74428539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"All-optical pseudorandom bit sequence generator","authors":"A. Poustie, K. Blow, R. Manning, A. Kelly","doi":"10.1364/cleo_europe.1998.cpd2.2","DOIUrl":"https://doi.org/10.1364/cleo_europe.1998.cpd2.2","url":null,"abstract":"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<m). At present, the experimental latency is several hundred bits at a IGHz clock rate and so we use multiples of lower length sequences in order to measure the performance of the design. We have experimentally demonstrated a maximal length 231-1 PRBS ({m,n}={713,552} ≡ 23 x {m,n}={31,24}) and also sub-maximal sequences. The figure below shows a digitally sampled part of the maximal 231-1 PRBS. The apparent amplitude modulation of the pulses is an artefact of the relatively low sampling rate (400Msamples/s). We were only able to record short temporal sequences since the repeat period of the PRBS is ~50s.","PeriodicalId":10610,"journal":{"name":"Conference on Lasers and Electro-Optics Europe","volume":"140 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77609370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of weld quality with normal and 30° incident laser beams","authors":"E. Ng, I. Watson","doi":"10.1364/cleo_europe.1998.cthh96","DOIUrl":"https://doi.org/10.1364/cleo_europe.1998.cthh96","url":null,"abstract":"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.","PeriodicalId":10610,"journal":{"name":"Conference on Lasers and Electro-Optics Europe","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81925499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laser Surface Modifications","authors":"H. Hügel","doi":"10.1364/cleo_europe.1998.cmb1","DOIUrl":"https://doi.org/10.1364/cleo_europe.1998.cmb1","url":null,"abstract":"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.","PeriodicalId":10610,"journal":{"name":"Conference on Lasers and Electro-Optics Europe","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80108712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Compact cw laser source for high-resolution spectroscopy between 6.8 and 12.5 μm","authors":"V. Petrov, C. Rempel, K. Stolberg, W. Schade","doi":"10.1364/cleo_europe.1998.cfh6","DOIUrl":"https://doi.org/10.1364/cleo_europe.1998.cfh6","url":null,"abstract":"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.","PeriodicalId":10610,"journal":{"name":"Conference on Lasers and Electro-Optics Europe","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84528159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}