The regional ecological positioning of one area is based on the region’s ecological orientation by the country or a larger region.Combined with the region’s natural geographical features,ecological background,main e...The regional ecological positioning of one area is based on the region’s ecological orientation by the country or a larger region.Combined with the region’s natural geographical features,ecological background,main ecological problems,regional ecological structure,pattern,process,function and service,etc.,the position of a certain area in ecological space,structure,process,function and service,etc.is determined through the analysis and research.Regional ecological positioning is an important prerequisite and core basis for regional ecological impact assessment.However,in the current regional ecological impact assessment,most of them have not analyzed and studied the regional ecological positioning.Due to the lack of research on regional ecological positioning,it is rare to apply the research results of regional ecological positioning to the establishment of regional ecological objectives and the construction of index system.Regional ecological positioning does not guide the direction of regional ecological protection and construction well,and there is a general tendency of regional ecological positioning being one-sided and slogan-based.This paper analyzes the necessity and importance of research of regional ecological positioning,puts forward the technology framework of study on regional ecological positioning.With regional ecological positioning research in planning ecological impact assessment of the Chengdu-Chongqing Economic Zone as an example,how to carry out the study on the regional ecological positioning and how to apply the results of the study on the regional ecological positioning in regional ecological impact assessment are explained and illustrated.展开更多
Single-mode lasing in whispering-gallery mode(WGM)microresonators is challenging to achieve.In bottle microresonators,the highly non-degenerated WGMs are spatially well-separated along the long-axis direction and prov...Single-mode lasing in whispering-gallery mode(WGM)microresonators is challenging to achieve.In bottle microresonators,the highly non-degenerated WGMs are spatially well-separated along the long-axis direction and provide mode-selection capability.In this work,by engineering the pump intensity to modify the spatial gain profiles of bottle microresonators,we demonstrate a simple and general approach to realizing single-mode WGM lasing in polymer bottle microresonators.The pump intensity is engineered into an interference distribution on the bottle microresonator surface.By tuning the spacing between axial positions of the interference pump patterns,the mode intensity profiles of single-bottle WGMs can be spatially overlapped with the interference stripes,intrinsically enabling single-mode lasing and selection.Attractive advantages of the system,including high sidemode suppression factors 420 dB,large spectral tunability 48 nm,low-lasing threshold and reversible control,are presented.Our demonstrated approach may have a variety of promising applications,ranging from tunable single-mode lasing and sensing to nonlinear optics.展开更多
Due to the lack of mode selection capability, single whispering-gallery-mode(WGM) lasing is a challenge to achieve. In bottle microresonators, the highly nondegenerated WGMs are spatially well-separated along the long...Due to the lack of mode selection capability, single whispering-gallery-mode(WGM) lasing is a challenge to achieve. In bottle microresonators, the highly nondegenerated WGMs are spatially well-separated along the long-axis direction and provide mode selection according to their axial mode numbers. In this work, we use a loss-engineering approach to suppress the higher-order WGMs and demonstrate single-mode lasing emission in small polymer bottle microresonators. The fiber tapers are not only used to couple pump light into the bottle microresonators to excite the WGMs but also to bring optical losses that are induced from the diameter mismatch between fiber tapers and microresonators. By adjusting the coupling positions, the diameters of fiber tapers, and the coupling angles, single fundamental-mode lasing is efficiently generated with side-mode suppression factors over 15 dB. Our loss-engineering approach is convenient just by moving the fiber taper and may findpromising applications in miniature tunable single-mode lasers and sensors.展开更多
We demonstrate an effective approach of mode suppression by simply using a tungsten probe to destroy the external neck surface of polymer microbottle resonators.The higher-order bottle modes with large axial orders,sp...We demonstrate an effective approach of mode suppression by simply using a tungsten probe to destroy the external neck surface of polymer microbottle resonators.The higher-order bottle modes with large axial orders,spatially located around the neck surface of the microresonator,will suffer large optical losses.Thus,excitation just with an ordinary free-space light beam will ensure direct generation of single fundamental bottle mode lasers.This method is with very low cost and convenient and can obtain high side-mode suppression factors.Our work demonstrated here may have promising applications such as in lasing and sensing devices.展开更多
基金Supported by Special Projects in Key Fields of Ordinary Colleges and Universities in Guangdong Province(Science and Technology Serving Rural Revitalization)(2021ZDZX4023)Construction Item of Teaching Quality and Teaching Reform Project in Guangdong Provincial Undergraduate Universities in 2021(YUEJIAOGAOHAN[2021]29)+3 种基金Quality Engineering and Teaching Reform Project of Zhaoqing University(zlgc 201931)Ideological and Political Construction Project of Environmental Engineering Courses,Curriculum Ideological and Political Construction Project of Zhaoqing University in 2020(ZHAOXUEYUAN[2020]95)Ideological and Political Construction Project of"Physical Pollution Control Engineering"Courses,Curriculum Ideological and Political Construction Project of Zhaoqing University in 2020(ZHAOXUEYUAN[2020]95)Innovation and Entrepreneurship Training Program for College Students of Zhaoqing University in 2022(X 202210580130)。
文摘The regional ecological positioning of one area is based on the region’s ecological orientation by the country or a larger region.Combined with the region’s natural geographical features,ecological background,main ecological problems,regional ecological structure,pattern,process,function and service,etc.,the position of a certain area in ecological space,structure,process,function and service,etc.is determined through the analysis and research.Regional ecological positioning is an important prerequisite and core basis for regional ecological impact assessment.However,in the current regional ecological impact assessment,most of them have not analyzed and studied the regional ecological positioning.Due to the lack of research on regional ecological positioning,it is rare to apply the research results of regional ecological positioning to the establishment of regional ecological objectives and the construction of index system.Regional ecological positioning does not guide the direction of regional ecological protection and construction well,and there is a general tendency of regional ecological positioning being one-sided and slogan-based.This paper analyzes the necessity and importance of research of regional ecological positioning,puts forward the technology framework of study on regional ecological positioning.With regional ecological positioning research in planning ecological impact assessment of the Chengdu-Chongqing Economic Zone as an example,how to carry out the study on the regional ecological positioning and how to apply the results of the study on the regional ecological positioning in regional ecological impact assessment are explained and illustrated.
基金supported by the National Natural Science Foundation of China(11674230)973 Program(2015CB352001)National Natural Science Foundation of China(11434005).
文摘Single-mode lasing in whispering-gallery mode(WGM)microresonators is challenging to achieve.In bottle microresonators,the highly non-degenerated WGMs are spatially well-separated along the long-axis direction and provide mode-selection capability.In this work,by engineering the pump intensity to modify the spatial gain profiles of bottle microresonators,we demonstrate a simple and general approach to realizing single-mode WGM lasing in polymer bottle microresonators.The pump intensity is engineered into an interference distribution on the bottle microresonator surface.By tuning the spacing between axial positions of the interference pump patterns,the mode intensity profiles of single-bottle WGMs can be spatially overlapped with the interference stripes,intrinsically enabling single-mode lasing and selection.Attractive advantages of the system,including high sidemode suppression factors 420 dB,large spectral tunability 48 nm,low-lasing threshold and reversible control,are presented.Our demonstrated approach may have a variety of promising applications,ranging from tunable single-mode lasing and sensing to nonlinear optics.
基金National Natural Science Foundation of China(NSFC)(11674230)973 Program(2015CB352001)
文摘Due to the lack of mode selection capability, single whispering-gallery-mode(WGM) lasing is a challenge to achieve. In bottle microresonators, the highly nondegenerated WGMs are spatially well-separated along the long-axis direction and provide mode selection according to their axial mode numbers. In this work, we use a loss-engineering approach to suppress the higher-order WGMs and demonstrate single-mode lasing emission in small polymer bottle microresonators. The fiber tapers are not only used to couple pump light into the bottle microresonators to excite the WGMs but also to bring optical losses that are induced from the diameter mismatch between fiber tapers and microresonators. By adjusting the coupling positions, the diameters of fiber tapers, and the coupling angles, single fundamental-mode lasing is efficiently generated with side-mode suppression factors over 15 dB. Our loss-engineering approach is convenient just by moving the fiber taper and may findpromising applications in miniature tunable single-mode lasers and sensors.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.11604210and 11674230)the Shanghai Rising-Star Program(No.18QA1403200)
文摘We demonstrate an effective approach of mode suppression by simply using a tungsten probe to destroy the external neck surface of polymer microbottle resonators.The higher-order bottle modes with large axial orders,spatially located around the neck surface of the microresonator,will suffer large optical losses.Thus,excitation just with an ordinary free-space light beam will ensure direct generation of single fundamental bottle mode lasers.This method is with very low cost and convenient and can obtain high side-mode suppression factors.Our work demonstrated here may have promising applications such as in lasing and sensing devices.
