Pub Date : 1900-01-01DOI: 10.1364/domo.1998.dtud.25
V. Baukens, A. Goulet, H. Thienpont, I. Veretennicoff, W. Cox, C. Guan
There has recently been significant progress in the development of arrays of fast and sensitive optoelectronic emitters, detectors and transceiver devices. If arrays of these devices are to be successfully incorporated into switching fabrics, data communication or information processing systems, then highly efficient optical systems must be developed to interconnect them. It is indeed important to minimise transmission losses, because the bandwidth of such data channels strongly depend on the amount of optical power impinging on the receivers. The highly divergent nature of some of these sources, such as Lambertian emitters and microcavity LEDs, does not facilitate this task, because of the high insertion losses at the input of the optical system. Moreover we want these systems to be compact, low cost, robust and easily assembled. In this paper we present a novel, hybrid and compact optical system, based on large diameter radial gradient refractive index (GRIN) lenses and microlenses that fulfills these requirements. We also model this system with raytracing software and evaluate its performances experimentally.
{"title":"GRIN-lens based optical interconnection systems for planes of micro emitters and detectors: Microlens arrays improve transmission efficiency","authors":"V. Baukens, A. Goulet, H. Thienpont, I. Veretennicoff, W. Cox, C. Guan","doi":"10.1364/domo.1998.dtud.25","DOIUrl":"https://doi.org/10.1364/domo.1998.dtud.25","url":null,"abstract":"There has recently been significant progress in the development of arrays of fast and sensitive optoelectronic emitters, detectors and transceiver devices. If arrays of these devices are to be successfully incorporated into switching fabrics, data communication or information processing systems, then highly efficient optical systems must be developed to interconnect them. It is indeed important to minimise transmission losses, because the bandwidth of such data channels strongly depend on the amount of optical power impinging on the receivers. The highly divergent nature of some of these sources, such as Lambertian emitters and microcavity LEDs, does not facilitate this task, because of the high insertion losses at the input of the optical system. Moreover we want these systems to be compact, low cost, robust and easily assembled. In this paper we present a novel, hybrid and compact optical system, based on large diameter radial gradient refractive index (GRIN) lenses and microlenses that fulfills these requirements. We also model this system with raytracing software and evaluate its performances experimentally.","PeriodicalId":301804,"journal":{"name":"Diffractive Optics and Micro-Optics","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":"126002548","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 : 1900-01-01DOI: 10.1364/domo.1998.dthc.4
X. Huang, Michael R. Wang
A compact beam shaper is required to efficiently convert coherent Gaussian beam into a flat-top beam for applications such as optical processing, laser radar, laser microfabrication, and laser scanning. A number of techniques for laser beam shaping have been developed so far [1-3]. Directly truncating the Gaussian beam with an aperture and weighting the Gaussian beam with a neutral density filter of proper amplitude transmittance profile have very poor energy efficiency. Binary shaper based on interlaced diffraction gratings suffers from its limited diffraction efficiency. Diffractive optics beam shaper fabricated by computer-generated hologram technique, by only changing the propagation phase patterns prior to diffraction focusing, is an effective beam shaper method.
{"title":"One-Step fabrication of a high-efficiency flat-top beam shaper","authors":"X. Huang, Michael R. Wang","doi":"10.1364/domo.1998.dthc.4","DOIUrl":"https://doi.org/10.1364/domo.1998.dthc.4","url":null,"abstract":"A compact beam shaper is required to efficiently convert coherent Gaussian beam into a flat-top beam for applications such as optical processing, laser radar, laser microfabrication, and laser scanning. A number of techniques for laser beam shaping have been developed so far [1-3]. Directly truncating the Gaussian beam with an aperture and weighting the Gaussian beam with a neutral density filter of proper amplitude transmittance profile have very poor energy efficiency. Binary shaper based on interlaced diffraction gratings suffers from its limited diffraction efficiency. Diffractive optics beam shaper fabricated by computer-generated hologram technique, by only changing the propagation phase patterns prior to diffraction focusing, is an effective beam shaper method.","PeriodicalId":301804,"journal":{"name":"Diffractive Optics and Micro-Optics","volume":"43 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":"124153308","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 : 1900-01-01DOI: 10.1364/domo.1996.jtub.18
Y. Sheng, D. Feng
Diffractive lenses for laser diode beam focusing collimating and coupling have wide applications. Large numerical aperture and high light efficiency are important issues for the coupling lenses. Numerical aperture of a typical laser diode beam can be as large as NA ~ 0.5. To capture the highly divergent beam the lens must have a low F-number of F/1 ~ F/2. Coupling the laser beam into an optic fiber with an acceptance angle of NA ~ 0.1 - 0.2 needs even larger numerical aperture of the lens.
{"title":"High efficiency fast diffractive lens for beam coupling","authors":"Y. Sheng, D. Feng","doi":"10.1364/domo.1996.jtub.18","DOIUrl":"https://doi.org/10.1364/domo.1996.jtub.18","url":null,"abstract":"Diffractive lenses for laser diode beam focusing collimating and coupling have wide applications. Large numerical aperture and high light efficiency are important issues for the coupling lenses. Numerical aperture of a typical laser diode beam can be as large as NA ~ 0.5. To capture the highly divergent beam the lens must have a low F-number of F/1 ~ F/2. Coupling the laser beam into an optic fiber with an acceptance angle of NA ~ 0.1 - 0.2 needs even larger numerical aperture of the lens.","PeriodicalId":301804,"journal":{"name":"Diffractive Optics and Micro-Optics","volume":"43 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":"127724527","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 : 1900-01-01DOI: 10.1364/domo.1996.jtub.12
J. Amako, T. Sonehara
Various approaches for flattop beam generation have been reported.1-4) Here we focus on a grating approach in which a phase grating is used to modulate a beam wavefront and shape its Fourier spectrum. We designed a grating-type beam shaper in an iterative manner, where an optimal grating phase is sought under the constraints of amplitude and phase both in the grating and Fourier planes.
{"title":"Flattop Beam Generation Using An Iteratively-Designed Binary Phase Grating","authors":"J. Amako, T. Sonehara","doi":"10.1364/domo.1996.jtub.12","DOIUrl":"https://doi.org/10.1364/domo.1996.jtub.12","url":null,"abstract":"Various approaches for flattop beam generation have been reported.1-4) Here we focus on a grating approach in which a phase grating is used to modulate a beam wavefront and shape its Fourier spectrum. We designed a grating-type beam shaper in an iterative manner, where an optimal grating phase is sought under the constraints of amplitude and phase both in the grating and Fourier planes.","PeriodicalId":301804,"journal":{"name":"Diffractive Optics and Micro-Optics","volume":"5 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":"131564154","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 : 1900-01-01DOI: 10.1364/domo.1996.dtha.2
M. T. Gale, T. Hessler, R. Kunz, H. Teichmann
Laser writing technology for the fabrication of continuous-relief micro-optical elements is being developed at a number of institutes worldwide [1,2]. It represents a very powerful and flexible fabrication technique and fits well to replication technology in which the resist surface-relief microstructure can be electroformed and replicated into plastic material. Fig. 1 illustrates the essential production steps involved.
{"title":"Fabrication of continuous-relief micro-optics: progress in laser writing and replication technology","authors":"M. T. Gale, T. Hessler, R. Kunz, H. Teichmann","doi":"10.1364/domo.1996.dtha.2","DOIUrl":"https://doi.org/10.1364/domo.1996.dtha.2","url":null,"abstract":"Laser writing technology for the fabrication of continuous-relief micro-optical elements is being developed at a number of institutes worldwide [1,2]. It represents a very powerful and flexible fabrication technique and fits well to replication technology in which the resist surface-relief microstructure can be electroformed and replicated into plastic material. Fig. 1 illustrates the essential production steps involved.","PeriodicalId":301804,"journal":{"name":"Diffractive Optics and Micro-Optics","volume":"316 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":"132546375","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 : 1900-01-01DOI: 10.1364/domo.1998.dtud.10
T. Hamano, M. Izutsu
Photonic band gap (PBG) structures have been studied due to interests in the control of spontaneous emission as well as due to their applications in optical devices. Some applications of PBG structures have been proposed, such as reflectors [1], cavities [2], waveguides [3] etc. In order to utilize them in these applications, 2-dimensional (2D) PBG structures are required to producing ‘complete’ band gaps. Thus, their necessary band gaps must be wide in any direction on plane and must operate in two orthogonal polarization states which are parallel and perpendicular to the pillars (or holes) of the structures.
{"title":"Novel Polarizers Using 2D Photonic Band Gap Structures","authors":"T. Hamano, M. Izutsu","doi":"10.1364/domo.1998.dtud.10","DOIUrl":"https://doi.org/10.1364/domo.1998.dtud.10","url":null,"abstract":"Photonic band gap (PBG) structures have been studied due to interests in the control of spontaneous emission as well as due to their applications in optical devices. Some applications of PBG structures have been proposed, such as reflectors [1], cavities [2], waveguides [3] etc. In order to utilize them in these applications, 2-dimensional (2D) PBG structures are required to producing ‘complete’ band gaps. Thus, their necessary band gaps must be wide in any direction on plane and must operate in two orthogonal polarization states which are parallel and perpendicular to the pillars (or holes) of the structures.","PeriodicalId":301804,"journal":{"name":"Diffractive Optics and Micro-Optics","volume":"52 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":"134570275","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}
Within the last 2 years Vertical Cavity Surface Emitting Lasers (VCSELs) have emerged from the research laboratory into the commercial marketplace as the component of choice for numerous applications, supplanting both LED and edge-emitting sources. The enormous success of VCSELs is attributed, in part, to their premium performance, producibility, and packaging perks. Namely, significantly lower operating currents and power dissipation at Gb/s data rates; wafer-level batch fabrication, testing, and utilization of the existing LED and III-V manufacturing infrastructure; more efficient coupling into fibers and simplified drive electronics.1 These attributes result directly from the laser’s inherent vertical geometry. This vertical cavity is essentially a zero-order thin-film Fabiy-Perot transmission filter, utilizing integral quarter-wave high-reflectance (> 99%) interference stacks referred to as distributed Bragg reflectors (DBRs). On a parallel front, it has recently been suggested that high reflectivity possible from guided-mode grating resonant filters (GMGRFs)2–4 may likewise serve to construct the high-Finesse vertical cavity, requiring minimal layers. These "resonant reflectors" may be designed to provide ultra-narrow bandwidth filters for a selected center wavelength and polarization with ≅100% in-band reflectance and ~30dB sideband suppression. These are very attractive properties for VCSELs and offer the potential as an enabling tool for modal engineering.
{"title":"Applications of Guided-mode resonant filters to VCSELs","authors":"R. Morgan, J. Cox, Robert Wilke, C. Ford","doi":"10.1364/domo.1998.dmb.1","DOIUrl":"https://doi.org/10.1364/domo.1998.dmb.1","url":null,"abstract":"Within the last 2 years Vertical Cavity Surface Emitting Lasers (VCSELs) have emerged from the research laboratory into the commercial marketplace as the component of choice for numerous applications, supplanting both LED and edge-emitting sources. The enormous success of VCSELs is attributed, in part, to their premium performance, producibility, and packaging perks. Namely, significantly lower operating currents and power dissipation at Gb/s data rates; wafer-level batch fabrication, testing, and utilization of the existing LED and III-V manufacturing infrastructure; more efficient coupling into fibers and simplified drive electronics.1 These attributes result directly from the laser’s inherent vertical geometry. This vertical cavity is essentially a zero-order thin-film Fabiy-Perot transmission filter, utilizing integral quarter-wave high-reflectance (> 99%) interference stacks referred to as distributed Bragg reflectors (DBRs). On a parallel front, it has recently been suggested that high reflectivity possible from guided-mode grating resonant filters (GMGRFs)2–4 may likewise serve to construct the high-Finesse vertical cavity, requiring minimal layers. These \"resonant reflectors\" may be designed to provide ultra-narrow bandwidth filters for a selected center wavelength and polarization with ≅100% in-band reflectance and ~30dB sideband suppression. These are very attractive properties for VCSELs and offer the potential as an enabling tool for modal engineering.","PeriodicalId":301804,"journal":{"name":"Diffractive Optics and Micro-Optics","volume":"295 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":"133104470","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}
This paper focuses on the application of genetic algorithms to the study and design of reflection and transmission filters based on the guided-mode resonance (GMR) effect in waveguide gratings.1–3 As genetic algorithms are well suited for problems with multidimensional, large search spaces4, they may be used effectively for optical filter design involving multiple periodic and homogeneous layers. In this work, the genetic algorithm library PGAPACK5 is combined with a forward code based on rigorous coupled-wave analysis6 in a new computer program that optimizes the merit function of a multilayer diffractive optical structure. Thus, a GMR-filter response with a given central wavelength, linewidth and sideband levels can be specified with a corresponding diffractive structure yielding approximately the specified response provided by the program. The net effect of this approach is that the inverse problem of finding a structure (i. e., layer thicknesses, refractive indices, fill factors, grating period) that yields a given filter response can be solved. In addition to providing useful filter designs, this approach may aid in the discovery of diffractive structures with profiles that may differ significantly from those ordinarily treated.
{"title":"Guided-mode resonance filters generated with genetic algorithms","authors":"S. Tibuleac, D. Shin, R. Magnusson, C. Zuffada","doi":"10.1364/domo.1998.dmb.3","DOIUrl":"https://doi.org/10.1364/domo.1998.dmb.3","url":null,"abstract":"This paper focuses on the application of genetic algorithms to the study and design of reflection and transmission filters based on the guided-mode resonance (GMR) effect in waveguide gratings.1–3 As genetic algorithms are well suited for problems with multidimensional, large search spaces4, they may be used effectively for optical filter design involving multiple periodic and homogeneous layers. In this work, the genetic algorithm library PGAPACK5 is combined with a forward code based on rigorous coupled-wave analysis6 in a new computer program that optimizes the merit function of a multilayer diffractive optical structure. Thus, a GMR-filter response with a given central wavelength, linewidth and sideband levels can be specified with a corresponding diffractive structure yielding approximately the specified response provided by the program. The net effect of this approach is that the inverse problem of finding a structure (i. e., layer thicknesses, refractive indices, fill factors, grating period) that yields a given filter response can be solved. In addition to providing useful filter designs, this approach may aid in the discovery of diffractive structures with profiles that may differ significantly from those ordinarily treated.","PeriodicalId":301804,"journal":{"name":"Diffractive Optics and Micro-Optics","volume":"93 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":"124549189","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 : 1900-01-01DOI: 10.1364/domo.1998.dtub.3
J. Mait, D. Prather, M. Mirotznik
Recent research1–9 has shown that if a binary-phase diffractive optical element (DOE) has features that are on the order of the illuminating wavelength, the performance limits set by scalar-based diffraction theory can be overcome. In fact, diffraction efficiencies in excess of 90% have been predicted for binary gratings that have subwavelength features.1,4,5 Due primarily to the availability of tools for modeling, the analysis and design of subwavelength DOEs (SWDOEs) has concentrated primarily on gratings.1-7,10 To overcome this limitation, we have developed numerical routines that use a boundary element method (BEM) to analyze diffraction from finite extent, aperiodic DOEs.11 In this paper we consider diffractive design, in particular, the design of diffractive lenses, subject to the constraints of fabrication.
{"title":"Scalar-Based Design of Binary Subwavelength Diffractive Lenses","authors":"J. Mait, D. Prather, M. Mirotznik","doi":"10.1364/domo.1998.dtub.3","DOIUrl":"https://doi.org/10.1364/domo.1998.dtub.3","url":null,"abstract":"Recent research1–9 has shown that if a binary-phase diffractive optical element (DOE) has features that are on the order of the illuminating wavelength, the performance limits set by scalar-based diffraction theory can be overcome. In fact, diffraction efficiencies in excess of 90% have been predicted for binary gratings that have subwavelength features.1,4,5 Due primarily to the availability of tools for modeling, the analysis and design of subwavelength DOEs (SWDOEs) has concentrated primarily on gratings.1-7,10 To overcome this limitation, we have developed numerical routines that use a boundary element method (BEM) to analyze diffraction from finite extent, aperiodic DOEs.11 In this paper we consider diffractive design, in particular, the design of diffractive lenses, subject to the constraints of fabrication.","PeriodicalId":301804,"journal":{"name":"Diffractive Optics and Micro-Optics","volume":"35 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":"117078293","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 : 1900-01-01DOI: 10.1364/domo.1996.jtub.25
B. Bakker
An existing analytical concept based on spectral decomposition has been developed more than hundred years ago, and is presently close to its limits in terms of performance and reliability, in particular, for complex samples. For molecules, a spectrum is a very complex pattern of sharp lines and continuous bands. So, in a classical spectrometer, detection is pruned to overlapping errors when two or more components of a sample have overlapping lines, and their separation is, generally, a non-unique problem. Indeed, a line can be assigned to, at least, two different transitions (in the same or different atom/molecules in a sample). Such an assignment based on line positions and transitions has limitations, and may not work at all for complex samples. As samples are getting more and more complex, the problem becomes increasingly intractable. In particular, algorithms and data processing to analyze complex spectra become very complex, require sophisticated peak analysis, etc. A mathematical "inversion" procedure for assignment and identification of components (species) also becomes unstable. That is, the current situation has all signs of a critical bottleneck, and requires an innovative approach. Meanwhile, selectivity is the first priority for many industries and applications. For instance, in the field of air toxics detection, the US EPA requires 189 components to be detected and regulated, and it is highly doubtful that any existing spectrometer is able to analyze reliably such a complex gaseous medium.
{"title":"A Computational Model for Holographic Sensing","authors":"B. Bakker","doi":"10.1364/domo.1996.jtub.25","DOIUrl":"https://doi.org/10.1364/domo.1996.jtub.25","url":null,"abstract":"An existing analytical concept based on spectral decomposition has been developed more than hundred years ago, and is presently close to its limits in terms of performance and reliability, in particular, for complex samples. For molecules, a spectrum is a very complex pattern of sharp lines and continuous bands. So, in a classical spectrometer, detection is pruned to overlapping errors when two or more components of a sample have overlapping lines, and their separation is, generally, a non-unique problem. Indeed, a line can be assigned to, at least, two different transitions (in the same or different atom/molecules in a sample). Such an assignment based on line positions and transitions has limitations, and may not work at all for complex samples. As samples are getting more and more complex, the problem becomes increasingly intractable. In particular, algorithms and data processing to analyze complex spectra become very complex, require sophisticated peak analysis, etc. A mathematical \"inversion\" procedure for assignment and identification of components (species) also becomes unstable. That is, the current situation has all signs of a critical bottleneck, and requires an innovative approach. Meanwhile, selectivity is the first priority for many industries and applications. For instance, in the field of air toxics detection, the US EPA requires 189 components to be detected and regulated, and it is highly doubtful that any existing spectrometer is able to analyze reliably such a complex gaseous medium.","PeriodicalId":301804,"journal":{"name":"Diffractive Optics and Micro-Optics","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":"115268530","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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