J. Mizeraczyk, Mostefa Mohamed-Seghir, I. Kostadinov, N. Sabotinov, E. S. Livingstone, C. E. Little
In this paper experimental results in high-precision processing of various materials carried out with a 10 W copper bromide laser are presented.
本文介绍了用10w溴化铜激光器对各种材料进行高精度加工的实验结果。
{"title":"10-W copper bromide laser for precision materials processing","authors":"J. Mizeraczyk, Mostefa Mohamed-Seghir, I. Kostadinov, N. Sabotinov, E. S. Livingstone, C. E. Little","doi":"10.1117/12.316624","DOIUrl":"https://doi.org/10.1117/12.316624","url":null,"abstract":"In this paper experimental results in high-precision processing of various materials carried out with a 10 W copper bromide laser are presented.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"102 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":"115364966","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}
In the paper there have been proposed methods for increasing the accuracy of spectronephelometrical investigations of medical objects. This method is based on the measurements, that use the combination of the same apparatus blocks and their different positioning. The distinctive feature of the discussed methods is their stability to the changes of apparatus constants, the pollution of the optical components, as well as the elimination or minimization of the used a priori information or assumptions about the object. The efficiency of diagnostics of the blood formed elements by the developed methods was estimated.
{"title":"Problems of laser spectronephelometry in medicine and some variants of their solution","authors":"M. Kugeiko, A. V. Barkova","doi":"10.1117/12.316636","DOIUrl":"https://doi.org/10.1117/12.316636","url":null,"abstract":"In the paper there have been proposed methods for increasing the accuracy of spectronephelometrical investigations of medical objects. This method is based on the measurements, that use the combination of the same apparatus blocks and their different positioning. The distinctive feature of the discussed methods is their stability to the changes of apparatus constants, the pollution of the optical components, as well as the elimination or minimization of the used a priori information or assumptions about the object. The efficiency of diagnostics of the blood formed elements by the developed methods was estimated.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"134 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":"125787088","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}
Referring to the work carried out in our laboratory, we review low-medium power diode pumped all solid state laser systems for scientific, bio-medical and industrial applications. Side- and end-pumping are discussed and compared for such a laser systems. End-pumped scheme is mainly exploited in this report. Coupling solutions and cavity design are described emphasizing energy deposition and extraction optimization, thermal lens effects, beam quality control and longitudinal mode control. Both cw- and quasi-cw-pumped lasers are considered, operating either in continuous wave, passive Q-switching, and mode-locking regimes. Intracavity and extracavity harmonic generation, optical parametric generation and short pulse generation are among the aims of these all-solid-state sources: some result of these applications are reported.
{"title":"Diode-pumped all-solid state lasers: solutions for scientific, biomedical, and industrial applications","authors":"A. Agnesi, G. Reali","doi":"10.1117/12.316564","DOIUrl":"https://doi.org/10.1117/12.316564","url":null,"abstract":"Referring to the work carried out in our laboratory, we review low-medium power diode pumped all solid state laser systems for scientific, bio-medical and industrial applications. Side- and end-pumping are discussed and compared for such a laser systems. End-pumped scheme is mainly exploited in this report. Coupling solutions and cavity design are described emphasizing energy deposition and extraction optimization, thermal lens effects, beam quality control and longitudinal mode control. Both cw- and quasi-cw-pumped lasers are considered, operating either in continuous wave, passive Q-switching, and mode-locking regimes. Intracavity and extracavity harmonic generation, optical parametric generation and short pulse generation are among the aims of these all-solid-state sources: some result of these applications are reported.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"334 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":"123775859","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}
We present a theoretical analysis of temporal autocorrelation functions of multiply scattered light in turbid dynamically heterogenous random media. Particular geometries of planar slab and cylindrical capillary inserted in an otherwise macroscopically homogeneous medium are considered. Analytical expressions for time autocorrelation functions of depolarized scattered electric field measured at the sample surface are derived assuming that scatterers dynamics inside dynamically heterogeneous region differs from that in surrounding medium. We show that space resolved measurements of the temporal autocorrelation function of multiply scattered light at the sample surface provide information on spatially heterogeneous particle dynamics inside the sample and allows one to image hidden dynamic inclusion under conditions of no static scattering contrast. Spatial contrast in this case is purely dynamic and can be provided by different particle sizes as well as by different types of particle dynamics inside the inclusion and in background medium. The limitations of presented theoretical approach are outlined. Finally, we estimate the performance of the imaging technique based on the considered theory.
{"title":"Diffusing wave spectroscopy in dynamically heterogeneous random media","authors":"S. E. Skipetrov, R. Maynard","doi":"10.1117/12.316593","DOIUrl":"https://doi.org/10.1117/12.316593","url":null,"abstract":"We present a theoretical analysis of temporal autocorrelation functions of multiply scattered light in turbid dynamically heterogenous random media. Particular geometries of planar slab and cylindrical capillary inserted in an otherwise macroscopically homogeneous medium are considered. Analytical expressions for time autocorrelation functions of depolarized scattered electric field measured at the sample surface are derived assuming that scatterers dynamics inside dynamically heterogeneous region differs from that in surrounding medium. We show that space resolved measurements of the temporal autocorrelation function of multiply scattered light at the sample surface provide information on spatially heterogeneous particle dynamics inside the sample and allows one to image hidden dynamic inclusion under conditions of no static scattering contrast. Spatial contrast in this case is purely dynamic and can be provided by different particle sizes as well as by different types of particle dynamics inside the inclusion and in background medium. The limitations of presented theoretical approach are outlined. Finally, we estimate the performance of the imaging technique based on the considered theory.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"14 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":"125365749","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}
M. Makropoulou, A. Papayannis, A. Serafetinides, Constantine Skordoulis
Pulsed laser ablation is well established as a universal tool for surface processing of organic polymer materials. The polymer ablation efficiency of different laser wavelengths, from 355 nm to 532 nm, is studied for short laser pulses, of nanosecond pulse duration. Ablation rates of polymers have been measured by irradiating the polymers using a pulsed Nd:YAG laser. This laser source produced pulses at the second and third harmonic simultaneously at (lambda) equals 532 nm and (lambda) equals 355 nm. Effective ablation was also observed by irradiating the polymer samples with the Raman-shifted Nd:YAG laser, at (lambda) equals 397.1 nm, in order to investigate comparatively the ablation efficiency at different laser settings. For transparent materials, in the corresponding ablation wavelengths and pulse width, the dependence of the ablation rate on the laser spot diameter and the laser energy fluence has been investigated. In general, the polymers used in this work show a more or less pronounced increase of the ablation rate with decreasing spot diameter for the same fluence, especially in the case of visible laser irradiation.
{"title":"VIS and UV laser ablation of polymers","authors":"M. Makropoulou, A. Papayannis, A. Serafetinides, Constantine Skordoulis","doi":"10.1117/12.316621","DOIUrl":"https://doi.org/10.1117/12.316621","url":null,"abstract":"Pulsed laser ablation is well established as a universal tool for surface processing of organic polymer materials. The polymer ablation efficiency of different laser wavelengths, from 355 nm to 532 nm, is studied for short laser pulses, of nanosecond pulse duration. Ablation rates of polymers have been measured by irradiating the polymers using a pulsed Nd:YAG laser. This laser source produced pulses at the second and third harmonic simultaneously at (lambda) equals 532 nm and (lambda) equals 355 nm. Effective ablation was also observed by irradiating the polymer samples with the Raman-shifted Nd:YAG laser, at (lambda) equals 397.1 nm, in order to investigate comparatively the ablation efficiency at different laser settings. For transparent materials, in the corresponding ablation wavelengths and pulse width, the dependence of the ablation rate on the laser spot diameter and the laser energy fluence has been investigated. In general, the polymers used in this work show a more or less pronounced increase of the ablation rate with decreasing spot diameter for the same fluence, especially in the case of visible laser irradiation.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"3 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":"126870465","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 evolution operator formalism, combined with appropriate decomposition techniques of exponential operators, has revealed an effective strategy to treat evolution-like problems in both classical and quantum context. The continuous original equation is turned into a set of finite- difference equations, which preserve at a discrete level the basic features of the corresponding continuous model. The resulting scheme is easy to be encoded and demands for less computer time. The method can be applied to the paraxial gaussian optics, described by the 1D parabolic wave equation. Within this context, the formalism generates an explicit difference scheme, which provides a flexible numerical integration procedure, accounting for higher-order aberrations as well.
{"title":"Decomposition techniques of exponential operators and paraxial light optics","authors":"G. Dattoli, A. Torre","doi":"10.1117/12.316574","DOIUrl":"https://doi.org/10.1117/12.316574","url":null,"abstract":"The evolution operator formalism, combined with appropriate decomposition techniques of exponential operators, has revealed an effective strategy to treat evolution-like problems in both classical and quantum context. The continuous original equation is turned into a set of finite- difference equations, which preserve at a discrete level the basic features of the corresponding continuous model. The resulting scheme is easy to be encoded and demands for less computer time. The method can be applied to the paraxial gaussian optics, described by the 1D parabolic wave equation. Within this context, the formalism generates an explicit difference scheme, which provides a flexible numerical integration procedure, accounting for higher-order aberrations as well.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"10 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":"128625859","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}
K. Ueberriegler, D. Fiedler, T. Verwanger, G. Schnitzhofer, E. Banieghbal, B. Krammer
Photodynamic tumor diagnosis and therapy is efficiently carried out by endogenous protoporphyrin IX as photosensitizer, induced by external addition of the precursor 5-aminolevulinic acid (ALA). In the present study, PpIX localization and photodynamically induced damage was investigated in normal and transformed human fibroblasts. PpIX formation reaches its maximum after incubation for at least 20 h with 700 (mu) g/m1 ALA, and increases with the pH- value. ALA has to be given 20-30 times more than external PpIX in order to produce the same cytotoxic damage. As detected by Low Light Imaging, PpIX is generated in the mitochondria, released to the cytoplasm and distributed to cytoplasma and nuclear membranes.The nucleus is not stained. Intracellular targets of PpIX damage after irradiation are mainly mitochondria, ER and nuclear membrane. The organelles show a decomposition pattern, which resembles apoptotic morphology and occurs faster in the co-cultivated transformed than in the normal cells. ALA-treated hepatocytes produce micronuclei and chromosomal aberrations, which indicates some mutagenic potential. Expression studies of the (proto)oncogenes c-myc and bcl-2 sublethally treated fibroblasts by quantitative RT-PCR show high deviations from the constitutive expression level, which are accompanied by cell cycle disturbances, indicating a possible precursor role to apoptosis introduction.
{"title":"In-vitro study on ALA-induced endogenous protoporphyrin IX as photosensitizer for photodynamic tumor diagnosis and therapy","authors":"K. Ueberriegler, D. Fiedler, T. Verwanger, G. Schnitzhofer, E. Banieghbal, B. Krammer","doi":"10.1117/12.316627","DOIUrl":"https://doi.org/10.1117/12.316627","url":null,"abstract":"Photodynamic tumor diagnosis and therapy is efficiently carried out by endogenous protoporphyrin IX as photosensitizer, induced by external addition of the precursor 5-aminolevulinic acid (ALA). In the present study, PpIX localization and photodynamically induced damage was investigated in normal and transformed human fibroblasts. PpIX formation reaches its maximum after incubation for at least 20 h with 700 (mu) g/m1 ALA, and increases with the pH- value. ALA has to be given 20-30 times more than external PpIX in order to produce the same cytotoxic damage. As detected by Low Light Imaging, PpIX is generated in the mitochondria, released to the cytoplasm and distributed to cytoplasma and nuclear membranes.The nucleus is not stained. Intracellular targets of PpIX damage after irradiation are mainly mitochondria, ER and nuclear membrane. The organelles show a decomposition pattern, which resembles apoptotic morphology and occurs faster in the co-cultivated transformed than in the normal cells. ALA-treated hepatocytes produce micronuclei and chromosomal aberrations, which indicates some mutagenic potential. Expression studies of the (proto)oncogenes c-myc and bcl-2 sublethally treated fibroblasts by quantitative RT-PCR show high deviations from the constitutive expression level, which are accompanied by cell cycle disturbances, indicating a possible precursor role to apoptosis introduction.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"11 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":"124331484","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}
In robot arc welding applications, in order to overcome inaccuracies of the robot itself and the workpiece, the tracking of the seam is of primal importance. To detect the seam, a novel sensor based on a laser scanner and using triangulation methods has been developed. A definite problem of the development is the difference in the optical power emitted by the arc which is in the range of hundreds of Watts and the power of the diode laser in the range of mW. In order to achieve good signal to noise ratio, it is necessary to select a wavelength where the glow of the arc is minimal and design an appropriate interference filter. For this purpose detailed measurements and analysis of the spectrum of the welding arc have been performed. The measurements extend for the UV region of the spectrum to the near IR region. The study was concentrated on the welding of ferrous metals using as shielding gas a mixture of 80 percent Ar and 20 percent CO2 and welding currents in the range of 100A to 160A. The measurements have revealed the presence of many strong emission lines in the spectrum.
{"title":"Spectrum analysis of the arc for laser-guided robot welding applications","authors":"G. Agapiou, C. Kassiouras, A. Serafetinides","doi":"10.1117/12.316616","DOIUrl":"https://doi.org/10.1117/12.316616","url":null,"abstract":"In robot arc welding applications, in order to overcome inaccuracies of the robot itself and the workpiece, the tracking of the seam is of primal importance. To detect the seam, a novel sensor based on a laser scanner and using triangulation methods has been developed. A definite problem of the development is the difference in the optical power emitted by the arc which is in the range of hundreds of Watts and the power of the diode laser in the range of mW. In order to achieve good signal to noise ratio, it is necessary to select a wavelength where the glow of the arc is minimal and design an appropriate interference filter. For this purpose detailed measurements and analysis of the spectrum of the welding arc have been performed. The measurements extend for the UV region of the spectrum to the near IR region. The study was concentrated on the welding of ferrous metals using as shielding gas a mixture of 80 percent Ar and 20 percent CO2 and welding currents in the range of 100A to 160A. The measurements have revealed the presence of many strong emission lines in the spectrum.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"26 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":"133325608","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. Corsi, M. Gabrysch, G. Modugno, F. Pavone, M. Inguscio
A DFB semiconductor diode laser spectrometer operating between 1 micrometers and 2 micrometers has been developed. High sensitivity detection measurements are carried on with different schemes, from pure linear absorption to two-tone frequency modulation. Results, including collisional lineshape parameters, are reported for various molecules of medical and environmental interest such as CO, CO2, H2S, NH3 and O2.
{"title":"High-sensitivity trace-gas monitoring for medical and environmental applications using a semiconductor diode laser","authors":"C. Corsi, M. Gabrysch, G. Modugno, F. Pavone, M. Inguscio","doi":"10.1117/12.316585","DOIUrl":"https://doi.org/10.1117/12.316585","url":null,"abstract":"A DFB semiconductor diode laser spectrometer operating between 1 micrometers and 2 micrometers has been developed. High sensitivity detection measurements are carried on with different schemes, from pure linear absorption to two-tone frequency modulation. Results, including collisional lineshape parameters, are reported for various molecules of medical and environmental interest such as CO, CO2, H2S, NH3 and O2.","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":"129554382","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}
T. Efthimiopoulos, D. Zevgolis, J. Katsenos, D. Zigos
Light amplification resulting from XeCl multiphoton dissociation of mercury-bromide was observed in the blue- green region between 502 and 505 nm. We report the formation of electronically excited HgBr radicals and measured the gain of the medium.
{"title":"Laser action from (B2Σ-X2Σ)HgBr induced by UV laser multiphoton dissociation of HgBr2: measurements and experimental results","authors":"T. Efthimiopoulos, D. Zevgolis, J. Katsenos, D. Zigos","doi":"10.1117/12.316554","DOIUrl":"https://doi.org/10.1117/12.316554","url":null,"abstract":"Light amplification resulting from XeCl multiphoton dissociation of mercury-bromide was observed in the blue- green region between 502 and 505 nm. We report the formation of electronically excited HgBr radicals and measured the gain of the medium.","PeriodicalId":373160,"journal":{"name":"GR-I International Conference on New Laser Technologies and Applications","volume":"137 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":"130804833","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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