Pub Date : 2019-10-17DOI: 10.1109/CLEOE-EQEC.2019.8872807
V. Bruno, S. Vezzoli, C. DeVault, V. Shalaev, A. Boltasseva, M. Clerici, M. Ferrera, D. Faccio
The dynamical control of material electromagnetic (EM) properties has recently been attracting significant interest. While a static design of the optical properties can provide a complete control of the momentum of a propagating wave, time-dependent materials allow the manipulation of its optical frequency. For instance, suppose a laser pulse incident on the interface between two media where one of them is rapidly changing refractive index in time. The temporal modulation of the boundary between the two media leads to a backward and forward propagating wave with a shifted spectrum [1,2]. This phenomenon, called photon acceleration, has been theoretically investigated in the last century, whilst experimental proof is harder to achieve for homogenous materials or surfaces due to the extremely large and fast changes of the refractive index required.
{"title":"Highly Efficient Frequency Shifting from Temporally Modulated Epsilon-Near-Zero Surfaces","authors":"V. Bruno, S. Vezzoli, C. DeVault, V. Shalaev, A. Boltasseva, M. Clerici, M. Ferrera, D. Faccio","doi":"10.1109/CLEOE-EQEC.2019.8872807","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2019.8872807","url":null,"abstract":"The dynamical control of material electromagnetic (EM) properties has recently been attracting significant interest. While a static design of the optical properties can provide a complete control of the momentum of a propagating wave, time-dependent materials allow the manipulation of its optical frequency. For instance, suppose a laser pulse incident on the interface between two media where one of them is rapidly changing refractive index in time. The temporal modulation of the boundary between the two media leads to a backward and forward propagating wave with a shifted spectrum [1,2]. This phenomenon, called photon acceleration, has been theoretically investigated in the last century, whilst experimental proof is harder to achieve for homogenous materials or surfaces due to the extremely large and fast changes of the refractive index required.","PeriodicalId":6714,"journal":{"name":"2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)","volume":"28 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2019-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78157611","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 : 2019-10-17DOI: 10.1109/CLEOE-EQEC.2019.8873280
F. Schlaepfer, M. Lucchini, Shunsuke A. Sato, M. Volkov, L. Kasmi, N. Hartmann, Á. Rubio, L. Gallmann, U. Keller
A fundamental understanding of ultrafast electron dynamics in solids induced by light is of great interest for future high-speed electro-optical devices operating in the petahertz frequency regime [1]. In the last years, a number of publications demonstrated the possibility to resolve and control carrier dynamics in semiconductors [2,3] and dielectrics [4,5] on the few- to sub-femtosecond time scale using attosecond transient absorption spectroscopy (ATAS). These experiments were performed with a non-resonant pump pulse, i.e. pump photon energies smaller than the corresponding band gap. Here in contrast, we resolve for the first time the attosecond carrier dynamics induced by a resonant intense laser pulse. We study the attosecond electronic response in gallium arsenide (GaAs), a technologically important narrow band gap semiconductor [6].
{"title":"Optically Driven Attosecond Electron Dynamics in III-V Semiconductors","authors":"F. Schlaepfer, M. Lucchini, Shunsuke A. Sato, M. Volkov, L. Kasmi, N. Hartmann, Á. Rubio, L. Gallmann, U. Keller","doi":"10.1109/CLEOE-EQEC.2019.8873280","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2019.8873280","url":null,"abstract":"A fundamental understanding of ultrafast electron dynamics in solids induced by light is of great interest for future high-speed electro-optical devices operating in the petahertz frequency regime [1]. In the last years, a number of publications demonstrated the possibility to resolve and control carrier dynamics in semiconductors [2,3] and dielectrics [4,5] on the few- to sub-femtosecond time scale using attosecond transient absorption spectroscopy (ATAS). These experiments were performed with a non-resonant pump pulse, i.e. pump photon energies smaller than the corresponding band gap. Here in contrast, we resolve for the first time the attosecond carrier dynamics induced by a resonant intense laser pulse. We study the attosecond electronic response in gallium arsenide (GaAs), a technologically important narrow band gap semiconductor [6].","PeriodicalId":6714,"journal":{"name":"2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)","volume":"22 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2019-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74252715","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 : 2019-10-17DOI: 10.1109/CLEOE-EQEC.2019.8872520
Haider Zia, Niklas M. Lüpken, T. Hellwig, C. Fallnich, K. Boiler
Supercontinuum generation (SCG), a process that generates a wide and coherent bandwidth of light, has become foundational in emergent optical technologies in a plethora of fields, such as optical coherence tomography (OCT), metrology (e.g., integrated photonic Kerr combs) and precision sensing. As advanced applications of SCG emerge, the requirements on the spectral bandwidth, the coherence, its temporal compressibility, and the quality of the optical spectral content (e.g., a uniformly flat spectral profile) are increasing. Moreover, as these technologies need not be restricted to the lab, the spectral conversion efficiency of SCG must increase from current technology that functions, e.g., in the tens of nJ pulse energy, to sub nJ levels.
{"title":"Sign-Alternating Dispersion Patterning for Supercontinuum Generation","authors":"Haider Zia, Niklas M. Lüpken, T. Hellwig, C. Fallnich, K. Boiler","doi":"10.1109/CLEOE-EQEC.2019.8872520","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2019.8872520","url":null,"abstract":"Supercontinuum generation (SCG), a process that generates a wide and coherent bandwidth of light, has become foundational in emergent optical technologies in a plethora of fields, such as optical coherence tomography (OCT), metrology (e.g., integrated photonic Kerr combs) and precision sensing. As advanced applications of SCG emerge, the requirements on the spectral bandwidth, the coherence, its temporal compressibility, and the quality of the optical spectral content (e.g., a uniformly flat spectral profile) are increasing. Moreover, as these technologies need not be restricted to the lab, the spectral conversion efficiency of SCG must increase from current technology that functions, e.g., in the tens of nJ pulse energy, to sub nJ levels.","PeriodicalId":6714,"journal":{"name":"2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)","volume":"706 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2019-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82654284","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 : 2019-10-17DOI: 10.1109/CLEOE-EQEC.2019.8871452
D. Bochek, I. Vatnik, D. Churkin, M. Sumetsky
In this report, we present a method of fabrication of Surface Nanoscale Axial Photonic (SNAP) bottle microresonators [1] by strong bending of an optical fiber. We experimentally demonstrate that bending of the optical fiber causes the nanometer-scale variation of its local effective radius (ERV) along the fiber axis, which can lead to the complete localization of whispering gallery modes (WGMs) and formation of SNAP bottle microresonators. The simplicity of the introduced method and the ability to tune the induced ERV mechanically is of great importance for the fabrication of robust and tunable SNAP devices such as delay lines [2].
{"title":"Complete Localization of Light and Tunable Bottle Microresonators Introduced by Bending of an Optical Fiber","authors":"D. Bochek, I. Vatnik, D. Churkin, M. Sumetsky","doi":"10.1109/CLEOE-EQEC.2019.8871452","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2019.8871452","url":null,"abstract":"In this report, we present a method of fabrication of Surface Nanoscale Axial Photonic (SNAP) bottle microresonators [1] by strong bending of an optical fiber. We experimentally demonstrate that bending of the optical fiber causes the nanometer-scale variation of its local effective radius (ERV) along the fiber axis, which can lead to the complete localization of whispering gallery modes (WGMs) and formation of SNAP bottle microresonators. The simplicity of the introduced method and the ability to tune the induced ERV mechanically is of great importance for the fabrication of robust and tunable SNAP devices such as delay lines [2].","PeriodicalId":6714,"journal":{"name":"2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)","volume":"1 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2019-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89636853","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 : 2019-10-10DOI: 10.1109/CLEOE-EQEC.2019.8873228
M. Frosz, R. Pennetta, Michael T. Enders, G. Ahmed, P. Russell
Single-ring hollow-core photonic crystal fibre (SR-PCF), consisting of a ring of thin-walled glass capillaries surrounding a central hollow core, can offer remarkably low transmission loss [1], and is finding applications in, e.g., wavelength conversion and pulse compression in gases, high-power beam delivery and circular dichroism [2]. As with all microstructured fibres, it is highly desirable to continuously measure the internal structural parameters (e.g. the capillary diameter) during fibre drawing. This would improve the yield of useful fibre lengths, as well as offering better control of structural uniformity along the fibre. Successful tapering of hollow-core fibres also requires a non-destructive method of verifying structural integrity along the taper.
{"title":"Non-Invasive Real-Time Characterization of Hollow-Core Photonic Crystal Fibres using Whispering Gallery Mode Spectroscopy","authors":"M. Frosz, R. Pennetta, Michael T. Enders, G. Ahmed, P. Russell","doi":"10.1109/CLEOE-EQEC.2019.8873228","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2019.8873228","url":null,"abstract":"Single-ring hollow-core photonic crystal fibre (SR-PCF), consisting of a ring of thin-walled glass capillaries surrounding a central hollow core, can offer remarkably low transmission loss [1], and is finding applications in, e.g., wavelength conversion and pulse compression in gases, high-power beam delivery and circular dichroism [2]. As with all microstructured fibres, it is highly desirable to continuously measure the internal structural parameters (e.g. the capillary diameter) during fibre drawing. This would improve the yield of useful fibre lengths, as well as offering better control of structural uniformity along the fibre. Successful tapering of hollow-core fibres also requires a non-destructive method of verifying structural integrity along the taper.","PeriodicalId":6714,"journal":{"name":"2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)","volume":"140 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2019-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88725300","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 : 2019-10-01DOI: 10.1109/CLEOE-EQEC.2019.8873304
Xi Cheng, Qianqian Huang, Chuanhang Zou, C. Mou, Baohua Qin, Zhijun Yan, Lin Zhang
In addition to some regular pulses such as conventional soliton (CS) and dissipative soliton (DS), passively mode-locked fiber lasers can also generate another type of distinctive pulse, i.e. the so-called noise-like pulse (NLP) [1]. Generally speaking, in NLP fiber lasers, NLP can be switched from CS or DS by increasing the pump power or adjusting the polarization controller (PC) [2]. However, as far as we know, multiple switchable generation between NLP and DS or CS have never been reported. We here show the multiple switchable phenomenon between NLP and DS from an Er-doped fiber laser (EDFL) based on nonlinear polarization rotation (NPR) for the first time. This kind of fiber laser not only facilitates the deep understanding of the properties and mechanisms of NLP but also paves a new way for the design of multi-functional light source.
{"title":"Multiple Switchable Generation between Noise-Like Pulse and Dissipative Soliton in an Er-Doped Fiber Laser Based on Nonlinear Polarization Rotation","authors":"Xi Cheng, Qianqian Huang, Chuanhang Zou, C. Mou, Baohua Qin, Zhijun Yan, Lin Zhang","doi":"10.1109/CLEOE-EQEC.2019.8873304","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2019.8873304","url":null,"abstract":"In addition to some regular pulses such as conventional soliton (CS) and dissipative soliton (DS), passively mode-locked fiber lasers can also generate another type of distinctive pulse, i.e. the so-called noise-like pulse (NLP) [1]. Generally speaking, in NLP fiber lasers, NLP can be switched from CS or DS by increasing the pump power or adjusting the polarization controller (PC) [2]. However, as far as we know, multiple switchable generation between NLP and DS or CS have never been reported. We here show the multiple switchable phenomenon between NLP and DS from an Er-doped fiber laser (EDFL) based on nonlinear polarization rotation (NPR) for the first time. This kind of fiber laser not only facilitates the deep understanding of the properties and mechanisms of NLP but also paves a new way for the design of multi-functional light source.","PeriodicalId":6714,"journal":{"name":"2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)","volume":"67 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76328333","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 : 2019-08-11DOI: 10.1109/CLEOE-EQEC.2019.8873063
M. Ivanov, I. Thiele, S. Skupin, D. Buožius, V. Vaičaitis
Terahertz (THz) radiation is of great current interest due to many applications such as nonlinear THz spectroscopy and imaging. One of the compact and effective methods to obtain very high THz field strengths and extremely broadband spectral widths is THz wave generation from plasma filaments formed in air by focused bichromatic femtosecond laser pulses consisting of the first and the second harmonics (FH, SH). Here we investigate the effect of an azimuthal phase modulation of the SH carrying an optical vortex charge on the intensity and phase distribution of the THz pulse emitted from the laser induced plasma filament in air. We present both experimental and theoretical results.
{"title":"Terahertz Wave Generation in Air by Femtosecond Optical Vortex Pulses","authors":"M. Ivanov, I. Thiele, S. Skupin, D. Buožius, V. Vaičaitis","doi":"10.1109/CLEOE-EQEC.2019.8873063","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2019.8873063","url":null,"abstract":"Terahertz (THz) radiation is of great current interest due to many applications such as nonlinear THz spectroscopy and imaging. One of the compact and effective methods to obtain very high THz field strengths and extremely broadband spectral widths is THz wave generation from plasma filaments formed in air by focused bichromatic femtosecond laser pulses consisting of the first and the second harmonics (FH, SH). Here we investigate the effect of an azimuthal phase modulation of the SH carrying an optical vortex charge on the intensity and phase distribution of the THz pulse emitted from the laser induced plasma filament in air. We present both experimental and theoretical results.","PeriodicalId":6714,"journal":{"name":"2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)","volume":"8 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2019-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84673752","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 : 2019-07-23DOI: 10.1109/CLEOE-EQEC.2019.8873336
F. Böhm, G. Verschaffelt, G. Van der Sande
We propose and test a new concept for a coherent Ising machine (CIM) with the goal of solving NP-hard optimization problems with a photonic system that is small in size and cheap to fabricate. CIMs are a promising concept for solving difficult optimization problems faster than on conventional digital computers [1]. Current CIMs are based on degenerate optical parametric oscillators (DOPOs) and use the optical phase of short laser pulses circulating in a ring cavity (∼1km circumference) to implement large-scale artificial Ising spin networks, which can in turn be used to implement the cost function of various optimization problems [2,3]. The natural tendency of the optical system to evolve to its ground state is then used to find the optimal solution. DOPO-based CIMs offer many advantages over quantum annealing hardware [1] and have demonstrated significant speed ups compared to conventional computers [3]. However, the large external cavity and the nonlinear optical processes required for the DOPO generation result in large and complex setups, which makes DOPO-based CIMs expensive and challenging to build. Additionally, the cavity has to be actively phase-locked, making it highly susceptible to external perturbations.
{"title":"Solving MAXCUT Optimization Problems with a Coherent Ising Machine Based on Opto-Electronic Oscillators","authors":"F. Böhm, G. Verschaffelt, G. Van der Sande","doi":"10.1109/CLEOE-EQEC.2019.8873336","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2019.8873336","url":null,"abstract":"We propose and test a new concept for a coherent Ising machine (CIM) with the goal of solving NP-hard optimization problems with a photonic system that is small in size and cheap to fabricate. CIMs are a promising concept for solving difficult optimization problems faster than on conventional digital computers [1]. Current CIMs are based on degenerate optical parametric oscillators (DOPOs) and use the optical phase of short laser pulses circulating in a ring cavity (∼1km circumference) to implement large-scale artificial Ising spin networks, which can in turn be used to implement the cost function of various optimization problems [2,3]. The natural tendency of the optical system to evolve to its ground state is then used to find the optimal solution. DOPO-based CIMs offer many advantages over quantum annealing hardware [1] and have demonstrated significant speed ups compared to conventional computers [3]. However, the large external cavity and the nonlinear optical processes required for the DOPO generation result in large and complex setups, which makes DOPO-based CIMs expensive and challenging to build. Additionally, the cavity has to be actively phase-locked, making it highly susceptible to external perturbations.","PeriodicalId":6714,"journal":{"name":"2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)","volume":"8 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2019-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76928395","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 : 2019-06-27DOI: 10.1109/CLEOE-EQEC.2019.8871445
Alexander Jantzen, P. Gow, S. L. Scholl, L. J. Boyd, Peter G. R. Smith, C. Holmes
Micromechanical devices are typically fabricated in expensive cleanrooms using techniques that are not conducive towards rapid and varied prototyping. This is typically because photolithography remains the main method for patterning of layers and should a small change be desired in the design, a new mask would have to be made, which is both a costly and slow process. This work reports a laser based approach for micromechanical diaphragm fabrication. The technique uses rapid thermal heating and subsequent quenching to a pattern a hard thermal oxide layer on a silicon substrate. This method used a computer controlled 9.3 micrometre wavelength CO2 laser beam to spot mark areas that were subsequently wet etched. This approach was found to be extremely repeatable and gave good consistency. It does not require cleanroom processing and is significantly more cost and time effective. Diaphragm feature size was observed to have a variability of <1% for diaphragms of several millimetres in size.
{"title":"Laser-Based Fabrication of Micromechanical Diaphragms for Pressure Sensing using Bragg Gratings","authors":"Alexander Jantzen, P. Gow, S. L. Scholl, L. J. Boyd, Peter G. R. Smith, C. Holmes","doi":"10.1109/CLEOE-EQEC.2019.8871445","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2019.8871445","url":null,"abstract":"Micromechanical devices are typically fabricated in expensive cleanrooms using techniques that are not conducive towards rapid and varied prototyping. This is typically because photolithography remains the main method for patterning of layers and should a small change be desired in the design, a new mask would have to be made, which is both a costly and slow process. This work reports a laser based approach for micromechanical diaphragm fabrication. The technique uses rapid thermal heating and subsequent quenching to a pattern a hard thermal oxide layer on a silicon substrate. This method used a computer controlled 9.3 micrometre wavelength CO2 laser beam to spot mark areas that were subsequently wet etched. This approach was found to be extremely repeatable and gave good consistency. It does not require cleanroom processing and is significantly more cost and time effective. Diaphragm feature size was observed to have a variability of <1% for diaphragms of several millimetres in size.","PeriodicalId":6714,"journal":{"name":"2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)","volume":"112 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2019-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80672983","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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