Datong Chen, H. Fetterman, Antao Chen, W. Steier, L. Dalton, Wenshen Wang, Yongqian Shi
Nonlinear electrooptic polymer materials have the advantages of fast response and low dispersion. Traveling wave devices made from these polymer materials have an intrinsic higher bandwidth compared with competing material systems. We reported earlier the demonstration of 60 GHz polymer electrooptic modulators, and have now extended this development to 94 GHz devices. Microwave circuit performance is the limiting factor in extending the frequency response of these devices. The resistive loss of the electrodes becomes higher as the frequency increases. Using optimized device parameters and improved processing techniques, we have designed and fabricated two types of improved electrodes which have low losses at high frequency. Our coplanar strips configuration requires in-plane poling while our new microstrip line electrode works with our standard corona poling process.
{"title":"High bandwidth polymer modulators","authors":"Datong Chen, H. Fetterman, Antao Chen, W. Steier, L. Dalton, Wenshen Wang, Yongqian Shi","doi":"10.1117/12.264232","DOIUrl":"https://doi.org/10.1117/12.264232","url":null,"abstract":"Nonlinear electrooptic polymer materials have the advantages of fast response and low dispersion. Traveling wave devices made from these polymer materials have an intrinsic higher bandwidth compared with competing material systems. We reported earlier the demonstration of 60 GHz polymer electrooptic modulators, and have now extended this development to 94 GHz devices. Microwave circuit performance is the limiting factor in extending the frequency response of these devices. The resistive loss of the electrodes becomes higher as the frequency increases. Using optimized device parameters and improved processing techniques, we have designed and fabricated two types of improved electrodes which have low losses at high frequency. Our coplanar strips configuration requires in-plane poling while our new microstrip line electrode works with our standard corona poling process.","PeriodicalId":332726,"journal":{"name":"Conference Proceedings LEOS'96 9th Annual Meeting IEEE Lasers and Electro-Optics Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127329007","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}
Pub Date : 1996-12-31DOI: 10.1109/LEOS.1996.565166
K. Choquette, W. Chow, G. R. Hadley, H. Hou, K. Geib
Summary form only given. In summary, we have developed an accurate first-principles analysis to probe the threshold properties of selectively oxidized 850 nm AlGaAs QW VCSELs. The analysis of our present VCSELs indicates that in order to achieve ultralow threshold, oxide aperture scattering loss and leakage currents must be addressed. The agreement between our calculations and experiment solidify our understanding and enable the identification of fundamental limitations of low threshold VCSEL operation. The performance and analysis of modified VCSEL designs will be reported.
{"title":"Properties of small-aperture selectively oxidized VCSELs","authors":"K. Choquette, W. Chow, G. R. Hadley, H. Hou, K. Geib","doi":"10.1109/LEOS.1996.565166","DOIUrl":"https://doi.org/10.1109/LEOS.1996.565166","url":null,"abstract":"Summary form only given. In summary, we have developed an accurate first-principles analysis to probe the threshold properties of selectively oxidized 850 nm AlGaAs QW VCSELs. The analysis of our present VCSELs indicates that in order to achieve ultralow threshold, oxide aperture scattering loss and leakage currents must be addressed. The agreement between our calculations and experiment solidify our understanding and enable the identification of fundamental limitations of low threshold VCSEL operation. The performance and analysis of modified VCSEL designs will be reported.","PeriodicalId":332726,"journal":{"name":"Conference Proceedings LEOS'96 9th Annual Meeting IEEE Lasers and Electro-Optics Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125993950","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}
Pub Date : 1996-12-01DOI: 10.1109/LEOS.1996.571657
G. Ortiz, C. Hains, J. Cheng, H. Hou, J. Zolper
In high density, parallel optical interconnect applications, it is often advantageous to monolithically integrate the photonic functions on a single substrate in order to achieve improved performance and to simplify packaging. It is also desirable to have an epilayer design that can incorporate many of these functions without compromising their individual performance. The monolithic integration of the optical source and photodetection functions is demonstrated here using a VCSEL and a resonance-enhanced photodetector (REPD), which share a common multiquantum-well active region that is enclosed within two different embedded resonance cavities. Each cavity is individually optimized to provide efficient operation for both the VCSEL and the REPD. Since optimum VCSEL performance requires very high mirror reflectivities, while optimum REPD performance for a REPD requires a cavity with lower reflectivities, the use ofa single design may compromise both. In our new design, however, the cavity of the REPD is embedded within the cavity of the VCSEL, so that the former cavity can be realized by chemically removing some of the AlAs/AlGaAs quarter-wave layers in the upper DBR mirror. The REPDs have achieved quantum efficiencies as high as 85%, while the VCSELs have achieved threshold current densities as low as 850 A/cm/sup 2/ and differential quantum efficiencies as high as 50%.
{"title":"Monolithic integration and individually-optimized operation of In/sub 0.2/Ga/sub 0.8/As vertical-cavity surface-emitting lasers and resonance-enhanced quantum well photodetectors","authors":"G. Ortiz, C. Hains, J. Cheng, H. Hou, J. Zolper","doi":"10.1109/LEOS.1996.571657","DOIUrl":"https://doi.org/10.1109/LEOS.1996.571657","url":null,"abstract":"In high density, parallel optical interconnect applications, it is often advantageous to monolithically integrate the photonic functions on a single substrate in order to achieve improved performance and to simplify packaging. It is also desirable to have an epilayer design that can incorporate many of these functions without compromising their individual performance. The monolithic integration of the optical source and photodetection functions is demonstrated here using a VCSEL and a resonance-enhanced photodetector (REPD), which share a common multiquantum-well active region that is enclosed within two different embedded resonance cavities. Each cavity is individually optimized to provide efficient operation for both the VCSEL and the REPD. Since optimum VCSEL performance requires very high mirror reflectivities, while optimum REPD performance for a REPD requires a cavity with lower reflectivities, the use ofa single design may compromise both. In our new design, however, the cavity of the REPD is embedded within the cavity of the VCSEL, so that the former cavity can be realized by chemically removing some of the AlAs/AlGaAs quarter-wave layers in the upper DBR mirror. The REPDs have achieved quantum efficiencies as high as 85%, while the VCSELs have achieved threshold current densities as low as 850 A/cm/sup 2/ and differential quantum efficiencies as high as 50%.","PeriodicalId":332726,"journal":{"name":"Conference Proceedings LEOS'96 9th Annual Meeting IEEE Lasers and Electro-Optics Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125398150","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}
Pub Date : 1996-12-01DOI: 10.1109/LEOS.1996.565162
F. Mccormick, S. Esener, P. Rentzepis
Two-photon 3-D memories are similar to multilayer optical disk systems with the potential for simple media fabrication, many layers, parallel access for high data transfer rates, and low raw bit error rates (BER). Orthogonal intersection of the writing beams may be used, or if ultra-short (e.g. <100 femtosecond) pulses are used, a counter-propagating arrangement is feasible. While single bits may be stored and recalled, parallel access of lines or planes of data is naturally accommodated in two-photon 3-D memories, to provide increased data transfer rates. Due to diffraction of the addressing beam as it propagates across the data image, there exists a tradeoff between the volumetric density of the memory and the parallelism, or data transfer rate. We have performed a variety of 3-D memory experiments to demonstrate writing, reading, and erasure, and recently we have begun system-level characterization experiments to evaluate this technology's practical potential. The progression of this evaluation has proceeded from the demonstration of multilayer recording of "noisy" images, to the qualitative improvement of those images to the point at which more quantitative techniques are needed to measure the performance of the media, recording, and reading systems.
{"title":"Engineering 2-photon optical data storage systems","authors":"F. Mccormick, S. Esener, P. Rentzepis","doi":"10.1109/LEOS.1996.565162","DOIUrl":"https://doi.org/10.1109/LEOS.1996.565162","url":null,"abstract":"Two-photon 3-D memories are similar to multilayer optical disk systems with the potential for simple media fabrication, many layers, parallel access for high data transfer rates, and low raw bit error rates (BER). Orthogonal intersection of the writing beams may be used, or if ultra-short (e.g. <100 femtosecond) pulses are used, a counter-propagating arrangement is feasible. While single bits may be stored and recalled, parallel access of lines or planes of data is naturally accommodated in two-photon 3-D memories, to provide increased data transfer rates. Due to diffraction of the addressing beam as it propagates across the data image, there exists a tradeoff between the volumetric density of the memory and the parallelism, or data transfer rate. We have performed a variety of 3-D memory experiments to demonstrate writing, reading, and erasure, and recently we have begun system-level characterization experiments to evaluate this technology's practical potential. The progression of this evaluation has proceeded from the demonstration of multilayer recording of \"noisy\" images, to the qualitative improvement of those images to the point at which more quantitative techniques are needed to measure the performance of the media, recording, and reading systems.","PeriodicalId":332726,"journal":{"name":"Conference Proceedings LEOS'96 9th Annual Meeting IEEE Lasers and Electro-Optics Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129668110","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}
Pub Date : 1996-12-01DOI: 10.1109/LEOS.1996.565149
W. Herzog, M. Unlu, B. Goldberg, G. H. Rhodes, C. Harder
We report mode structure and beam propagation analysis of high power strained (In,Ga)As quantum well lasers using the super-resolution capabilities of near-field scanning optical microscopy (NSOM). We are able to directly measure the optical beam waist and astigmatism by imaging the output of the laser diode at various heights above the device facet. In the near-field we observe spatial shifts in the position of the optical field between different spectral components of the laser diode emission.
{"title":"Near-field analysis of beam properties of InGaAs ridge lasers","authors":"W. Herzog, M. Unlu, B. Goldberg, G. H. Rhodes, C. Harder","doi":"10.1109/LEOS.1996.565149","DOIUrl":"https://doi.org/10.1109/LEOS.1996.565149","url":null,"abstract":"We report mode structure and beam propagation analysis of high power strained (In,Ga)As quantum well lasers using the super-resolution capabilities of near-field scanning optical microscopy (NSOM). We are able to directly measure the optical beam waist and astigmatism by imaging the output of the laser diode at various heights above the device facet. In the near-field we observe spatial shifts in the position of the optical field between different spectral components of the laser diode emission.","PeriodicalId":332726,"journal":{"name":"Conference Proceedings LEOS'96 9th Annual Meeting IEEE Lasers and Electro-Optics Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123388196","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}
Pub Date : 1996-12-01DOI: 10.1109/LEOS.1996.565265
Tae Geun Kim, E. Kim, C. Son, Seong-Il Kim, Jichai Jeong, S. Min, Si-Jong Leem, Jong Il Jun, H. Lee, J. Park, T. Seong, S. Jun
We report quantum wire (QWR) diode lasers incorporating a p-n junction blocking layer between buffer layers, instead of proton implantation. A n-GaAs buffer and a 2-/spl mu/m-thick p-GaAs QW layer for current blocking were grown on (100) GaAs substrates. Structure and optical properties of the QWR have been investigated using transmission electron microscopy (TEM) and low temperature photoluminescence (PL).
{"title":"Lasing characteristics of GaAs/AlGaAs quantum wire laser and its array with an effective p-n junction current blocking layer","authors":"Tae Geun Kim, E. Kim, C. Son, Seong-Il Kim, Jichai Jeong, S. Min, Si-Jong Leem, Jong Il Jun, H. Lee, J. Park, T. Seong, S. Jun","doi":"10.1109/LEOS.1996.565265","DOIUrl":"https://doi.org/10.1109/LEOS.1996.565265","url":null,"abstract":"We report quantum wire (QWR) diode lasers incorporating a p-n junction blocking layer between buffer layers, instead of proton implantation. A n-GaAs buffer and a 2-/spl mu/m-thick p-GaAs QW layer for current blocking were grown on (100) GaAs substrates. Structure and optical properties of the QWR have been investigated using transmission electron microscopy (TEM) and low temperature photoluminescence (PL).","PeriodicalId":332726,"journal":{"name":"Conference Proceedings LEOS'96 9th Annual Meeting IEEE Lasers and Electro-Optics Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115992731","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}
Pub Date : 1996-12-01DOI: 10.1109/LEOS.1996.571578
S. Koehler, K. Il Kang, I. Glesk, P. Prucnal
Summary form only given. In conclusion, we have demonstrated a 3-stage, 8-bit optical packet compressor that compresses an incoming packet at a bit rate of 100 Mb/s to an outgoing bit rate of 100 Gb/s. Optical packet compressors, which are a subset of tunable delay lines, are necessary for ultrafast packet-switched all-optical time division multiplexed networks.
{"title":"Optical packet compressor operating at 100 Gb/s","authors":"S. Koehler, K. Il Kang, I. Glesk, P. Prucnal","doi":"10.1109/LEOS.1996.571578","DOIUrl":"https://doi.org/10.1109/LEOS.1996.571578","url":null,"abstract":"Summary form only given. In conclusion, we have demonstrated a 3-stage, 8-bit optical packet compressor that compresses an incoming packet at a bit rate of 100 Mb/s to an outgoing bit rate of 100 Gb/s. Optical packet compressors, which are a subset of tunable delay lines, are necessary for ultrafast packet-switched all-optical time division multiplexed networks.","PeriodicalId":332726,"journal":{"name":"Conference Proceedings LEOS'96 9th Annual Meeting IEEE Lasers and Electro-Optics Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126709845","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}
Pub Date : 1996-12-01DOI: 10.1109/LEOS.1996.565301
I. Gannot, R. Waynant
Summary form only given. The fast growing field of lasers in medicine with This talk will be concentrated on the results and state of the art of the work done by groups developing flexible waveguide medical laser beam applications. Material used to produce these waveguides consist of tubings made of Teflon, fused silica, a few types of metal and sapphire. Each of these materials carry with them their own degree of flexibility, internal reflecting, and refracting layers and also made of different materials and are produced by a number of procedures. With the introduction of mid-infrared free electron lasers (FELs) a tunable laser source became available for testing broadband transmission waveguides. This laser has a unique pulse structure, but its high peak powers can serve as an excellent testing tool for waveguides damage.
{"title":"Optical waveguides for infrared laser sources","authors":"I. Gannot, R. Waynant","doi":"10.1109/LEOS.1996.565301","DOIUrl":"https://doi.org/10.1109/LEOS.1996.565301","url":null,"abstract":"Summary form only given. The fast growing field of lasers in medicine with This talk will be concentrated on the results and state of the art of the work done by groups developing flexible waveguide medical laser beam applications. Material used to produce these waveguides consist of tubings made of Teflon, fused silica, a few types of metal and sapphire. Each of these materials carry with them their own degree of flexibility, internal reflecting, and refracting layers and also made of different materials and are produced by a number of procedures. With the introduction of mid-infrared free electron lasers (FELs) a tunable laser source became available for testing broadband transmission waveguides. This laser has a unique pulse structure, but its high peak powers can serve as an excellent testing tool for waveguides damage.","PeriodicalId":332726,"journal":{"name":"Conference Proceedings LEOS'96 9th Annual Meeting IEEE Lasers and Electro-Optics Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133299500","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}
Pub Date : 1996-12-01DOI: 10.1109/LEOS.1996.565297
K. Choquette, K. Geib, R. Hull, H. Hou, K. Lear, H. Chui, B. E. Hammons, J. Nevers
In summary, buried oxides formed from the wet oxidation of AlGaAs alloys, rather than AlAs, are found to be superior in terms of oxidation isotropy, mechanical stability, and strain. It is not surprising that VCSELs using AlGaAs oxide layers as current apertures have shown promising reliability as compared to VCSELs using AlAs layers. Comparisons of lifetime data for VCSELs with differing oxide layers will be presented. The beneficial properties of oxides converted from AlGaAs alloys are found to provide robust device processing of reliable VCSELs and may play an important role in other advanced optoelectronic devices.
{"title":"Wet oxidation of AlGaAs vs. AlAs: A little gallium is good","authors":"K. Choquette, K. Geib, R. Hull, H. Hou, K. Lear, H. Chui, B. E. Hammons, J. Nevers","doi":"10.1109/LEOS.1996.565297","DOIUrl":"https://doi.org/10.1109/LEOS.1996.565297","url":null,"abstract":"In summary, buried oxides formed from the wet oxidation of AlGaAs alloys, rather than AlAs, are found to be superior in terms of oxidation isotropy, mechanical stability, and strain. It is not surprising that VCSELs using AlGaAs oxide layers as current apertures have shown promising reliability as compared to VCSELs using AlAs layers. Comparisons of lifetime data for VCSELs with differing oxide layers will be presented. The beneficial properties of oxides converted from AlGaAs alloys are found to provide robust device processing of reliable VCSELs and may play an important role in other advanced optoelectronic devices.","PeriodicalId":332726,"journal":{"name":"Conference Proceedings LEOS'96 9th Annual Meeting IEEE Lasers and Electro-Optics Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128188852","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}
Pub Date : 1996-11-18DOI: 10.1109/LEOS.1996.565239
F. Choa, J.Y. Fan, P. Liu, J. Sipior, G. Rao, G. Carter, Y.J. Chen
We study time-resolved-spectra of InGaN and GaN diodes with a short electrical pulse. LEDs with four different structures were studied: the bulk InGaN/GaN blue LED (/spl lambda//sub peak/ = 450 nm); the InGaN single quantum well (SQW) blue LED (/spl lambda//sub peak/ = 470 nm); the InGaN SQW green LED (/spl lambda//sub peak/ = 525 nm); and the Zn disordered GaN active layer (/spl lambda//sub peak/ = 430 nm). When pumped with short electrical pulses, some of them can generate UV light. The electrical pump time-resolved spectrum studies provide a convenient tool to investigate the recombination process in the GaN material system. The results show that the UV emissions from bulk GaN and bulk InGaN materials, and the blue as well as the green emissions from the high efficiency InGaN SQW LEDs, correspond to bandedge transitions.
{"title":"Time resolved spectra study of GaN light emitting diodes (LEDs)","authors":"F. Choa, J.Y. Fan, P. Liu, J. Sipior, G. Rao, G. Carter, Y.J. Chen","doi":"10.1109/LEOS.1996.565239","DOIUrl":"https://doi.org/10.1109/LEOS.1996.565239","url":null,"abstract":"We study time-resolved-spectra of InGaN and GaN diodes with a short electrical pulse. LEDs with four different structures were studied: the bulk InGaN/GaN blue LED (/spl lambda//sub peak/ = 450 nm); the InGaN single quantum well (SQW) blue LED (/spl lambda//sub peak/ = 470 nm); the InGaN SQW green LED (/spl lambda//sub peak/ = 525 nm); and the Zn disordered GaN active layer (/spl lambda//sub peak/ = 430 nm). When pumped with short electrical pulses, some of them can generate UV light. The electrical pump time-resolved spectrum studies provide a convenient tool to investigate the recombination process in the GaN material system. The results show that the UV emissions from bulk GaN and bulk InGaN materials, and the blue as well as the green emissions from the high efficiency InGaN SQW LEDs, correspond to bandedge transitions.","PeriodicalId":332726,"journal":{"name":"Conference Proceedings LEOS'96 9th Annual Meeting IEEE Lasers and Electro-Optics Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124269361","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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