C. Panagopoulos, C. Giokas, P. E. Agathocleous, A. Carabelas
Zinc specimens were irradiated with a high power excimer laser. Under specific lasing conditions, zinc oxide was detected on the x-rays diffraction spectra. The surface roughness of laser treated specimens was found to be depended upon the lasing conditions. The surface layers of laser treated zinc specimens presented higher microhardness as compared to the untreated zinc specimens.
{"title":"Laser surface treatment of zinc","authors":"C. Panagopoulos, C. Giokas, P. E. Agathocleous, A. Carabelas","doi":"10.1117/12.316609","DOIUrl":"https://doi.org/10.1117/12.316609","url":null,"abstract":"Zinc specimens were irradiated with a high power excimer laser. Under specific lasing conditions, zinc oxide was detected on the x-rays diffraction spectra. The surface roughness of laser treated specimens was found to be depended upon the lasing conditions. The surface layers of laser treated zinc specimens presented higher microhardness as compared to the untreated zinc specimens.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123867381","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}
L. Bartolini, A. Bordone, L. Businaro, M. Ferri De Collibus, G. Fornetti, L. Morici, C. Poggi
A coherent laser sensor, able to achieve measurement of absolute and relative distance of real targets, has been developed for advanced robotic applications. A brief theoretical description of the expected behavior of such system is reported for static and dynamic targets; the theoretical range error dependence from the signal to noise ratio is also described. Experimental results for measurements of static and vibrating real targets are discussed.
{"title":"Coherent laser sensor for robotic applications","authors":"L. Bartolini, A. Bordone, L. Businaro, M. Ferri De Collibus, G. Fornetti, L. Morici, C. Poggi","doi":"10.1117/12.316615","DOIUrl":"https://doi.org/10.1117/12.316615","url":null,"abstract":"A coherent laser sensor, able to achieve measurement of absolute and relative distance of real targets, has been developed for advanced robotic applications. A brief theoretical description of the expected behavior of such system is reported for static and dynamic targets; the theoretical range error dependence from the signal to noise ratio is also described. Experimental results for measurements of static and vibrating real targets are discussed.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133485530","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}
Recoil-induced resonances have been observed in pump-probe spectroscopy with cold atoms. On the other hand, a model for collective atomic recoil laser has been developed by R. Bonifacio and co-workers. These two systems rely on the recoil effect due to the absorption or the emission of a photon by an atom and share may features. In this paper, we shall investigate the relationship between the two models and clarify the underlying physics. We'll review also the experimental results.
{"title":"Recoil-induced gain and collective atomic recoil laser","authors":"P. Verkerk","doi":"10.1117/12.316608","DOIUrl":"https://doi.org/10.1117/12.316608","url":null,"abstract":"Recoil-induced resonances have been observed in pump-probe spectroscopy with cold atoms. On the other hand, a model for collective atomic recoil laser has been developed by R. Bonifacio and co-workers. These two systems rely on the recoil effect due to the absorption or the emission of a photon by an atom and share may features. In this paper, we shall investigate the relationship between the two models and clarify the underlying physics. We'll review also the experimental results.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133720542","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}
Z. Horváth, M. Erdélyi, G. Szabó, Z. Bor, F. Tittel, Joseph R. Cavallaro
A new concept for generating zero order Bessel beams was studied. A point source illuminated a Fabry-Perot etalon, which produced a concentric interference ring system in front of an imaging lens.If the lens aperture was adjusted so that it transmitted the first ring only and blocked all others, a zero order Bessel bean was generated beyond the lens. The spatial intensity distribution beyond the lens was calculated numerically using a wave optical model. The calculated and measured axial intensity distributions were compared. An approximate analytical expression was derived to describe the radial intensity distribution in planes perpendicular to the optical axis.
{"title":"Generation of zero-order Bessel beams with Fabry-Perot interferometer","authors":"Z. Horváth, M. Erdélyi, G. Szabó, Z. Bor, F. Tittel, Joseph R. Cavallaro","doi":"10.1117/12.316568","DOIUrl":"https://doi.org/10.1117/12.316568","url":null,"abstract":"A new concept for generating zero order Bessel beams was studied. A point source illuminated a Fabry-Perot etalon, which produced a concentric interference ring system in front of an imaging lens.If the lens aperture was adjusted so that it transmitted the first ring only and blocked all others, a zero order Bessel bean was generated beyond the lens. The spatial intensity distribution beyond the lens was calculated numerically using a wave optical model. The calculated and measured axial intensity distributions were compared. An approximate analytical expression was derived to describe the radial intensity distribution in planes perpendicular to the optical axis.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122173068","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}
G. Daurelio, A. Ludovico, C. Panagopoulos, Corrado Tundo
Even if many steels and alloys have been welded on the last years, nowadays there are some other stainless steel alloys that need a further comprehension when they have to be welded. Typically these alloys are martensitic and precipitation hardening ones that still present some problems to be weld, i.e. hot cracks, fragile beads, an excessive grain size and other surface defects. In this work some martensitic stainless steels of which a AISI 420B, a AISI 440C and a AISI 630 have been studied. The last one is always with a martensitic structure but, in particular, some interesting mechanical properties are reached by a precipitation hardening process. This research has experimented and studied the mechanical and technological properties of the welds obtained on the above cited AISI 420B, AISI 440C and AISI 630, welded by 1.5 kW CO2 laser. The results have also been compared with the ones obtained on ferritic stainless steels AISI 430 and 430F. A technological characterization of the welds has followed as metallographic tests and evaluations, microhardness, tensile and fatigue tests.
{"title":"Ferritic, martensitic, and precipitation hardening stainless steel laser weldings","authors":"G. Daurelio, A. Ludovico, C. Panagopoulos, Corrado Tundo","doi":"10.1117/12.316611","DOIUrl":"https://doi.org/10.1117/12.316611","url":null,"abstract":"Even if many steels and alloys have been welded on the last years, nowadays there are some other stainless steel alloys that need a further comprehension when they have to be welded. Typically these alloys are martensitic and precipitation hardening ones that still present some problems to be weld, i.e. hot cracks, fragile beads, an excessive grain size and other surface defects. In this work some martensitic stainless steels of which a AISI 420B, a AISI 440C and a AISI 630 have been studied. The last one is always with a martensitic structure but, in particular, some interesting mechanical properties are reached by a precipitation hardening process. This research has experimented and studied the mechanical and technological properties of the welds obtained on the above cited AISI 420B, AISI 440C and AISI 630, welded by 1.5 kW CO2 laser. The results have also been compared with the ones obtained on ferritic stainless steels AISI 430 and 430F. A technological characterization of the welds has followed as metallographic tests and evaluations, microhardness, tensile and fatigue tests.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"183 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125161385","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}
C. Kosmidis, K. Ledingham, H. Kılıç, T. McCanny, R. P. Singhal, D. Smith, A. Langley
The 90 femtosecond laser induced fragmentation at 375 nm for a number of different nitro-molecules is compared to that induced by a nanosecond laser at the same wavelength by means of time-of-flight mass spectrometry. The potential of femtosecond laser mass spectrometry for analytical purposes is discussed.
{"title":"Molecular fragmentation induced by a femtosecond laser","authors":"C. Kosmidis, K. Ledingham, H. Kılıç, T. McCanny, R. P. Singhal, D. Smith, A. Langley","doi":"10.1117/12.316582","DOIUrl":"https://doi.org/10.1117/12.316582","url":null,"abstract":"The 90 femtosecond laser induced fragmentation at 375 nm for a number of different nitro-molecules is compared to that induced by a nanosecond laser at the same wavelength by means of time-of-flight mass spectrometry. The potential of femtosecond laser mass spectrometry for analytical purposes is discussed.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125481285","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}
The fluorescence spectrum of rhodamine 6G incorporated in thin surfactant films demonstrates an extensive narrowing of the spectral width at relatively low excitation light fluence due to coherent scattering caused by molecular aggregates present in the film.
{"title":"Spectral narrowing in the emission of rhodamine 6G incorporated in thin surfactant films","authors":"E. Stathatos, S. Couris, P. Lianos","doi":"10.1117/12.316587","DOIUrl":"https://doi.org/10.1117/12.316587","url":null,"abstract":"The fluorescence spectrum of rhodamine 6G incorporated in thin surfactant films demonstrates an extensive narrowing of the spectral width at relatively low excitation light fluence due to coherent scattering caused by molecular aggregates present in the film.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"3423 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129075116","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}
Coherent detection, as a process for demodulation of an optical signal, is used to a great extent in modern optical communications. In some configurations of this technique, the information which exists in the frequency or the phase of the optical signal can be derived by using the same beam as a carrier and as a local-oscillator signal too. In this communication, we present a theoretical analysis of such a self-homodyne system, which is composed of a laser source, an electrooptic modulator, a photodetector and all the necessary optical components. The whole analysis is accompanied with a PC-supported program, which offers the possibility to study the system for various kinds of optical polarization but with the same incident optical power on the photodetector, independently of the various optical components.Furthermore, this program provides the possibility of changing the respective values at will, after we have introduce direct and alternating voltage as a signal. Finally, the study of the various harmonics of the output signal's spectrum gives the possibility to discover the advantages that the circular polarization offers compared with other kinds of polarization.
{"title":"Optical self-homodyne coherent system using elliptically or circularly polarized laser light","authors":"G. A. Vaitsos, N. Théofanous","doi":"10.1117/12.316566","DOIUrl":"https://doi.org/10.1117/12.316566","url":null,"abstract":"Coherent detection, as a process for demodulation of an optical signal, is used to a great extent in modern optical communications. In some configurations of this technique, the information which exists in the frequency or the phase of the optical signal can be derived by using the same beam as a carrier and as a local-oscillator signal too. In this communication, we present a theoretical analysis of such a self-homodyne system, which is composed of a laser source, an electrooptic modulator, a photodetector and all the necessary optical components. The whole analysis is accompanied with a PC-supported program, which offers the possibility to study the system for various kinds of optical polarization but with the same incident optical power on the photodetector, independently of the various optical components.Furthermore, this program provides the possibility of changing the respective values at will, after we have introduce direct and alternating voltage as a signal. Finally, the study of the various harmonics of the output signal's spectrum gives the possibility to discover the advantages that the circular polarization offers compared with other kinds of polarization.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114070329","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}
The development of conical structures on the surface of excimer laser ablated polymers, is studied. It is demonstrated that this phenomenon has a lower threshold and an upper limit fluence which values depend on the material. The lower value is equivalent of the ablation threshold of the sample, below which the etch does not occur. In accordance with our assumption the upper limit corresponds to the ablation threshold of the particulate impurities which are responsible for the formation of cones, because these impurities remove from the surface of the polymers with the other ablating fragments when the fluence exceeds the upper limit. The dependence of the apex angles of the cones on the fluence and the number of pulses is investigated. A simple etching model based on the diffraction and interference theories is proposed to explain the formation of the conical structure.
{"title":"Conical structures produced by excimer laser irradiation of polymers","authors":"B. Hopp, Z. Bor, E. Homolya, E. Mihalik","doi":"10.1117/12.316622","DOIUrl":"https://doi.org/10.1117/12.316622","url":null,"abstract":"The development of conical structures on the surface of excimer laser ablated polymers, is studied. It is demonstrated that this phenomenon has a lower threshold and an upper limit fluence which values depend on the material. The lower value is equivalent of the ablation threshold of the sample, below which the etch does not occur. In accordance with our assumption the upper limit corresponds to the ablation threshold of the particulate impurities which are responsible for the formation of cones, because these impurities remove from the surface of the polymers with the other ablating fragments when the fluence exceeds the upper limit. The dependence of the apex angles of the cones on the fluence and the number of pulses is investigated. A simple etching model based on the diffraction and interference theories is proposed to explain the formation of the conical structure.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115160365","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}
G. Baldacchini, E. Burattini, A. Grilli, A. Raco, A. Mancini, R. Montereali, A. Pace
Low energy electron beam irradiation of LiF single crystals and polycrystalline films induces efficient formation of stable laser active defects emitting in the visible spectral range at room temperature, together with a consistent increase of the real part of the refractive index in the same wavelength interval. The use of electron lithography techniques look promising for the realization of active channel waveguides.
{"title":"Electron beam lithography on LiF films for integrated active optical waveguides","authors":"G. Baldacchini, E. Burattini, A. Grilli, A. Raco, A. Mancini, R. Montereali, A. Pace","doi":"10.1117/12.316557","DOIUrl":"https://doi.org/10.1117/12.316557","url":null,"abstract":"Low energy electron beam irradiation of LiF single crystals and polycrystalline films induces efficient formation of stable laser active defects emitting in the visible spectral range at room temperature, together with a consistent increase of the real part of the refractive index in the same wavelength interval. The use of electron lithography techniques look promising for the realization of active channel waveguides.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114555042","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}
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