Large laser systems for fusion research employ disk laser amplifiers at the output of each amplifier chain owing to the superior nonlinear performance of large-aperture (d > 10-cm) disk amplifiers over rod amplifiers of the same aperture. This superior performance arises from three sources: (1) generally higher attainable gain coefficients; (2) reduction in beam intensity inside the Brewster’s angle disks; and (3) the air spaces between successive disks permitting diffraction to diverge small-scale self-focusing filaments.
{"title":"Design of disk laser amplifiers for laser fusion applications","authors":"W. Fountain, W. Hagen, G. Linford","doi":"10.1364/cleos.1976.tha5","DOIUrl":"https://doi.org/10.1364/cleos.1976.tha5","url":null,"abstract":"Large laser systems for fusion research employ disk laser amplifiers at the output of each amplifier chain owing to the superior nonlinear performance of large-aperture (d > 10-cm) disk amplifiers over rod amplifiers of the same aperture. This superior performance arises from three sources:\u0000 (1) generally higher attainable gain coefficients;\u0000 (2) reduction in beam intensity inside the Brewster’s angle disks; and\u0000 (3) the air spaces between successive disks permitting diffraction to diverge small-scale self-focusing filaments.","PeriodicalId":301658,"journal":{"name":"Conference on Laser and Electrooptical Systems","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125824694","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}
Analysis of the light scattered by individual particles passing through a focused laser beam has recently become a common technique for characterizing air pollution aerosols. Early optical particulate analyzers utilized the light scattered in a single field of view to classify particles by size, but were hampered by relatively low resolution. This was due to effects of the index of refraction on the functional dependence of the scattered intensity on particle diameters1 and to variations in incident light intensity within the sensitive volume, which is Gaussian for laser beams.
{"title":"Uncertainties in particle size distributions measured with ratio-type single particle counters","authors":"E. Hirleman, S. Wittig","doi":"10.1364/cleos.1976.tuf4","DOIUrl":"https://doi.org/10.1364/cleos.1976.tuf4","url":null,"abstract":"Analysis of the light scattered by individual particles passing through a focused laser beam has recently become a common technique for characterizing air pollution aerosols. Early optical particulate analyzers utilized the light scattered in a single field of view to classify particles by size, but were hampered by relatively low resolution. This was due to effects of the index of refraction on the functional dependence of the scattered intensity on particle diameters1 and to variations in incident light intensity within the sensitive volume, which is Gaussian for laser beams.","PeriodicalId":301658,"journal":{"name":"Conference on Laser and Electrooptical Systems","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129505671","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}
High-density information recording and replication using surface-relief structures is a well established process in phonograph record and video disk production. In this talk, we describe a promising new development—the recording of two-dimensional black/white and color images by surface-relief phase gratings. These can be replicated rapidly and inexpensively by hot embossing into clear thermoplastic sheets and are well suited for information dissemination in a compact format, e.g., microfiche. Unlike holographically encoded surface-relief images,1,2 they can be displayed with 100% efficiency in conventional optical projectors designed for photographic transparencies. Unlike photographic materials, however, they absorb no light and hence are free from overheating and color fading problems.
{"title":"Image recording and display by embossable surface-relief structures","authors":"R. Engelbrecht, M. T. Gale, K. Knop","doi":"10.1364/cleos.1976.tud3","DOIUrl":"https://doi.org/10.1364/cleos.1976.tud3","url":null,"abstract":"High-density information recording and replication using surface-relief structures is a well established process in phonograph record and video disk production. In this talk, we describe a promising new development—the recording of two-dimensional black/white and color images by surface-relief phase gratings. These can be replicated rapidly and inexpensively by hot embossing into clear thermoplastic sheets and are well suited for information dissemination in a compact format, e.g., microfiche. Unlike holographically encoded surface-relief images,1,2 they can be displayed with 100% efficiency in conventional optical projectors designed for photographic transparencies. Unlike photographic materials, however, they absorb no light and hence are free from overheating and color fading problems.","PeriodicalId":301658,"journal":{"name":"Conference on Laser and Electrooptical Systems","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124534270","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 implications of high density focal plane arrays (>5000 detectors) upon the design and performance of next generation thermal imaging systems are discussed. The system design tradeoffs with respect to increased fields of view, improved sensitivity, and resolution are presented.
{"title":"Trends in next generation thermal imaging using integrated focal planes","authors":"Lloyd M. Candell, Paul J. Beckett","doi":"10.1364/cleos.1976.thc5","DOIUrl":"https://doi.org/10.1364/cleos.1976.thc5","url":null,"abstract":"The implications of high density focal plane arrays (>5000 detectors) upon the design and performance of next generation thermal imaging systems are discussed. The system design tradeoffs with respect to increased fields of view, improved sensitivity, and resolution are presented.","PeriodicalId":301658,"journal":{"name":"Conference on Laser and Electrooptical Systems","volume":"183 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124608894","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}
F. Chen, M. Didomenico, P. W. Dorman, M. Karr, T. Rich, P. Shumate, R. Smith
A feedback-stabilized GaAIAs injection laser optical communication source for transmission of NRZ data at 44.7 Mb/sec has been built and tested. Standard ECL input levels operate the emitter-coupled driver circuitry in which the stripe geometry double-heterostructure GaAIAs laser diode (λ = 825 nm) appears as a collector load. The laser is pre-biased near threshold by a separate feedback-stabilizing circuit. This circuit, utilizing an 800-kHz operational amplifier, compares the optical output measured from the back mirror of the laser using a PIN photodiode with data-pattern reference. In this way, closed-loop control of the prebias current makes the optical output insensitive to thermal effects and component aging. The driver–feedback components are assembled on thick-film hybrid integrated circuits. The laser, indium soldered to a gold-plated copper stud, and the thick-film driver circuit are mounted on an aluminum heat sink which forms the body of the driver package. A 40-cm Teflon-sheathed connectorized section of optical fiber is brought through the aluminum housing, strain relieved, and epoxied in place after positioning near the front mirror of the laser. Efficient coupling (50% or greater) between the laser and optical fiber is achieved by melting a spherical lens on the tip of the fiber. The driver package accessed through pins connected to the thick-film circuit is completed by filling the active volume of the heat sink with casting epoxy. The feedback package is of similar design but has only electrical inputs and outputs. The two-package subsystem launches a minimum of 1-mW peak power into a fiber with a ≈0.002-in. graded-index core. The extinction ratio is typically 15:1; peak-to-peak amplitude variation in the output is ~8%. The subsystem operates from 5°C to 55°C and tolerates ±5 % variations in the +5-V and -5.2-V supplies.
{"title":"GaAIAs laser transmitter for optical fiber transmission systems","authors":"F. Chen, M. Didomenico, P. W. Dorman, M. Karr, T. Rich, P. Shumate, R. Smith","doi":"10.1364/cleos.1976.the6","DOIUrl":"https://doi.org/10.1364/cleos.1976.the6","url":null,"abstract":"A feedback-stabilized GaAIAs injection laser optical communication source for transmission of NRZ data at 44.7 Mb/sec has been built and tested. Standard ECL input levels operate the emitter-coupled driver circuitry in which the stripe geometry double-heterostructure GaAIAs laser diode (λ = 825 nm) appears as a collector load. The laser is pre-biased near threshold by a separate feedback-stabilizing circuit. This circuit, utilizing an 800-kHz operational amplifier, compares the optical output measured from the back mirror of the laser using a PIN photodiode with data-pattern reference. In this way, closed-loop control of the prebias current makes the optical output insensitive to thermal effects and component aging. The driver–feedback components are assembled on thick-film hybrid integrated circuits. The laser, indium soldered to a gold-plated copper stud, and the thick-film driver circuit are mounted on an aluminum heat sink which forms the body of the driver package. A 40-cm Teflon-sheathed connectorized section of optical fiber is brought through the aluminum housing, strain relieved, and epoxied in place after positioning near the front mirror of the laser. Efficient coupling (50% or greater) between the laser and optical fiber is achieved by melting a spherical lens on the tip of the fiber. The driver package accessed through pins connected to the thick-film circuit is completed by filling the active volume of the heat sink with casting epoxy. The feedback package is of similar design but has only electrical inputs and outputs. The two-package subsystem launches a minimum of 1-mW peak power into a fiber with a ≈0.002-in. graded-index core. The extinction ratio is typically 15:1; peak-to-peak amplitude variation in the output is ~8%. The subsystem operates from 5°C to 55°C and tolerates ±5 % variations in the +5-V and -5.2-V supplies.","PeriodicalId":301658,"journal":{"name":"Conference on Laser and Electrooptical Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116530999","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 report on the development and proving of a rugged, wide bandwidth modulatable laser of relatively low cost. Conventional laser modulation systems employ external electrooptic (EO) or acoustooptic (AO) modulators.1,2 In the He–Ne case de modulation has been used. In applications such as laser beam recording the EO and AO modulators suffer various shortcomings, the principles of which are high cost, sensitivity to alignment, and imperfect extinction. Current modulation of the He–Ne laser is power-limited, bandwidth-limited, and can result in reduced tube life.
{"title":"Modulatable lasers for systems applications","authors":"J. D. Hawkins, W. Shull, T. Reynolds, M. Dowley","doi":"10.1364/cleos.1976.wd2","DOIUrl":"https://doi.org/10.1364/cleos.1976.wd2","url":null,"abstract":"We report on the development and proving of a rugged, wide bandwidth modulatable laser of relatively low cost. Conventional laser modulation systems employ external electrooptic (EO) or acoustooptic (AO) modulators.1,2 In the He–Ne case de modulation has been used. In applications such as laser beam recording the EO and AO modulators suffer various shortcomings, the principles of which are high cost, sensitivity to alignment, and imperfect extinction. Current modulation of the He–Ne laser is power-limited, bandwidth-limited, and can result in reduced tube life.","PeriodicalId":301658,"journal":{"name":"Conference on Laser and Electrooptical Systems","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126657934","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}
Since the pioneering work by Kaminow1 and others in the early Sixties, there has been a continuing interest in obtaining broadband low power microwave light modulators for a number of applications, ranging from optical communication and data processing systems2 to active Q switching and mode-locking of lasers.3 The work reported here was prompted by the fast pulse amplitude and phase control requirements of high-power laser fusion experiments and their associated diagnostics, where it is desirable, often mandatory, to perform optical gating or temporal pulse shaping operations in the sub-100-psec range. In this paper, we consider the problem of designing and constructing ultrafast electrooptic (EO) modulator devices capable of producing optical transmission risetimes shorter than 100 psec.
{"title":"Design and application of ultrafast KD*P electrooptic modulators","authors":"B. C. Johnson, D. Anafi","doi":"10.1364/cleos.1976.wa7","DOIUrl":"https://doi.org/10.1364/cleos.1976.wa7","url":null,"abstract":"Since the pioneering work by Kaminow1 and others in the early Sixties, there has been a continuing interest in obtaining broadband low power microwave light modulators for a number of applications, ranging from optical communication and data processing systems2 to active Q switching and mode-locking of lasers.3 The work reported here was prompted by the fast pulse amplitude and phase control requirements of high-power laser fusion experiments and their associated diagnostics, where it is desirable, often mandatory, to perform optical gating or temporal pulse shaping operations in the sub-100-psec range. In this paper, we consider the problem of designing and constructing ultrafast electrooptic (EO) modulator devices capable of producing optical transmission risetimes shorter than 100 psec.","PeriodicalId":301658,"journal":{"name":"Conference on Laser and Electrooptical Systems","volume":"130 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127045666","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}
Methods using laser Doppler velocimeters have been developed for measuring the dynamic relaxation time (τ p ) of aerosol particles and droplets. For real-time measurement of aerodynamic size spectra in the range of 0.2-50.0 μm in diameter, the most promising methods employ (1) acoustic excitation, for the size range of 0.2-5.0 μm in diameter, and (2) gravity settling, for the size range of 5.0-50.0 μm in diameter. Both methods have been applied to rapid in situ measurement of the size distribution of stable and unstable aerosols. Experimental results indicate that these newly developed methods compliment the existing methods of real-time aerosol size analysis.
{"title":"Aerosol sizing by laser Doppler relaxation-time measurement","authors":"M. Mazumder, S. N. Nichols, R. Overbey","doi":"10.1364/cleos.1976.tuf3","DOIUrl":"https://doi.org/10.1364/cleos.1976.tuf3","url":null,"abstract":"Methods using laser Doppler velocimeters have been developed for measuring the dynamic relaxation time (τ\u0000 p\u0000 ) of aerosol particles and droplets. For real-time measurement of aerodynamic size spectra in the range of 0.2-50.0 μm in diameter, the most promising methods employ (1) acoustic excitation, for the size range of 0.2-5.0 μm in diameter, and (2) gravity settling, for the size range of 5.0-50.0 μm in diameter. Both methods have been applied to rapid in situ measurement of the size distribution of stable and unstable aerosols. Experimental results indicate that these newly developed methods compliment the existing methods of real-time aerosol size analysis.","PeriodicalId":301658,"journal":{"name":"Conference on Laser and Electrooptical Systems","volume":"177 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124367163","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}
A status report summarizes the improved performance characteristics resulting from the application of restricted area contacts to single and double heterojunction laser structures. A geometric description of the process known as the stripe geometry contact is given as it relates to both GaAs and AIGaAs injection lasers. Application of the striped contacts to the fabrication of both pulsed and cw lasers has resulted in significant improvements in both performance and reliability of these devices. Data are presented that establish the superior device performance and reliability of both high peak power pulsed devices and room temperature cw lasers. The data include extended operating life tests for both pulsed and cw devices, comparisons of catastrophic damage limits, power output efficiency, as well as output and threshold current as a function of temperature. Radiation patterns, risetime, and polarization characteristics are also described. The paper also summarizes characteristics of cw injection lasers which can be supplied in a variety of packaging configurations. These devices have demonstrated analog modulation bandwidths well in excess of 100 MHz and appear well suited to use with available fiber optics materials having transmission windows in the 820-nm range.
{"title":"Recent developments in injection lasers","authors":"J. T. O'Brien, A. C. Limm, F. R. Hughes","doi":"10.1364/cleos.1976.wb4","DOIUrl":"https://doi.org/10.1364/cleos.1976.wb4","url":null,"abstract":"A status report summarizes the improved performance characteristics resulting from the application of restricted area contacts to single and double heterojunction laser structures. A geometric description of the process known as the stripe geometry contact is given as it relates to both GaAs and AIGaAs injection lasers. Application of the striped contacts to the fabrication of both pulsed and cw lasers has resulted in significant improvements in both performance and reliability of these devices. Data are presented that establish the superior device performance and reliability of both high peak power pulsed devices and room temperature cw lasers. The data include extended operating life tests for both pulsed and cw devices, comparisons of catastrophic damage limits, power output efficiency, as well as output and threshold current as a function of temperature. Radiation patterns, risetime, and polarization characteristics are also described. The paper also summarizes characteristics of cw injection lasers which can be supplied in a variety of packaging configurations. These devices have demonstrated analog modulation bandwidths well in excess of 100 MHz and appear well suited to use with available fiber optics materials having transmission windows in the 820-nm range.","PeriodicalId":301658,"journal":{"name":"Conference on Laser and Electrooptical Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134249357","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}
Trees are among the natural resources that are becoming less abundant and more costly. The trend to utilize as much as possible of each harvested tree is well established and will continue for both economic and ecological reasons. This paper considers an automated system designed to increase the percentage of useful lumber (the yield) obtained from millwork grades of softwood.
{"title":"Increasing production yields with a laser scanner lumber inspection system","authors":"P. Mueller, Raymond T. Hebert","doi":"10.1364/cleos.1976.tua6","DOIUrl":"https://doi.org/10.1364/cleos.1976.tua6","url":null,"abstract":"Trees are among the natural resources that are becoming less abundant and more costly. The trend to utilize as much as possible of each harvested tree is well established and will continue for both economic and ecological reasons. This paper considers an automated system designed to increase the percentage of useful lumber (the yield) obtained from millwork grades of softwood.","PeriodicalId":301658,"journal":{"name":"Conference on Laser and Electrooptical Systems","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134346590","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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