Topological phases and their associated multiple edge states are studied by constructing a one-dimensional non-unitary multi-period quantum walk with parity-time symmetry.It is shown that large topological numbers can...Topological phases and their associated multiple edge states are studied by constructing a one-dimensional non-unitary multi-period quantum walk with parity-time symmetry.It is shown that large topological numbers can be obtained when choosing an appropriate time frame.The maximum value of the winding number can reach the number of periods in the one-step evolution operator.The validity of the bulk-edge correspondence is confirmed,while for an odd-period quantum walk and an even-period quantum walk,they have different configurations of the 0-energy edge state andπ-energy edge state.On the boundary,two kinds of edge states always coexist in equal amount for the odd-period quantum walk,however three cases including equal amount,unequal amount or even only one type may occur for the even-period quantum walk.展开更多
Age-related macular degeneration(AMD)has been classified in two groups,neovascular and non-neovascular,which historically has been synonymous with exudative and non-exudative,respectively.Neovascular AMD occurs when p...Age-related macular degeneration(AMD)has been classified in two groups,neovascular and non-neovascular,which historically has been synonymous with exudative and non-exudative,respectively.Neovascular AMD occurs when pathologic blood vessels,choroidal展开更多
Diabetic neuropathy(DN)is,at least in part,associated with the functional attenuation of vasa nervorum,the microvascular structure of peripheral nerves.Microvascular imaging options for vasa nervorum still remain limi...Diabetic neuropathy(DN)is,at least in part,associated with the functional attenuation of vasa nervorum,the microvascular structure of peripheral nerves.Microvascular imaging options for vasa nervorum still remain limited.In this work,optical microangiography(OMAG),a volumetric,label-free imaging technique,is utilized for characterizing,with high resolution,blood perfusion of peripheral nerve in diabetic mice.We demonstrate that OMAG is able to visualize the structure of microvasculature and to quantify the changes of dynamic blood flow and vessel diameters during administration of vessel stimulant in both diabetic and normal mice.The results indicate the potential of OMAG to assess the blood supply of nerve involved in the pathology and treatment of DN.展开更多
The cause of glaucoma,a disease defined by degeneration of retinal ganglion cells associated with cupping of the optic nerve head(ONH)and progressive vision loss,continues to be debated despite numerous advances in op...The cause of glaucoma,a disease defined by degeneration of retinal ganglion cells associated with cupping of the optic nerve head(ONH)and progressive vision loss,continues to be debated despite numerous advances in ophthalmic imaging and diagnostics.Although elevated intraocular pressure is often implicated,many studies,using a variety of imaging techniques including plain fundus photography,fluorescein angiography,laser Doppler flowmetry,and color Doppler ultrasound(1-4),have suggested that insufficiencies of ONH circulation may play a role in glaucoma pathogenesis.While all of these imaging modalities have been informative,each has a set of limitations,including low spatial resolution,invasiveness,restriction to superficial vessels,lack of repeatability,and modality specific artifacts.Optical coherence tomography angiography(OCTA),an imaging technology that can produce high resolution,three-dimensional images of fundus microcirculation,is well suited to overcome many of these limitations(5).展开更多
Hybrid metal-dielectric structures combine the advantages of both metal and dielectric materials,enabling high-confined but low-loss magnetic and electric resonances through deliberate arrangements.However,their poten...Hybrid metal-dielectric structures combine the advantages of both metal and dielectric materials,enabling high-confined but low-loss magnetic and electric resonances through deliberate arrangements.However,their potential for enhancing magnetic emission has yet to be fully explored.Here,we study the magnetic and electric Purcell enhancement supported by a hybrid structure composed of a dielectric nanoring and a silver nanorod.This structure enables low Ohmic loss and highlyconfined field under the mode hybridization of magnetic resonances on a nanoring and electric resonances on a nanorod in the optical communication band.Thus,the 60-fold magnetic Purcell enhancement and 45-fold electric Purcell enhancement can be achieved.Over 90%of the radiation can be transmitted to the far field.For the sufficiently large Purcell enhancement,the position of emitter has a tolerance of several tens of nanometers,which brings convenience to experimental fabrications.Moreover,an array formed by this hybrid nanostructure can further enhance the magnetic Purcell factors.The system provides a feasible option to selectively excite magnetic and electric emission in integrated photonic circuits.It may also facilitate brighter magnetic emission sources and light-emitting metasurfaces with a more straightforward design.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.12004231).
文摘Topological phases and their associated multiple edge states are studied by constructing a one-dimensional non-unitary multi-period quantum walk with parity-time symmetry.It is shown that large topological numbers can be obtained when choosing an appropriate time frame.The maximum value of the winding number can reach the number of periods in the one-step evolution operator.The validity of the bulk-edge correspondence is confirmed,while for an odd-period quantum walk and an even-period quantum walk,they have different configurations of the 0-energy edge state andπ-energy edge state.On the boundary,two kinds of edge states always coexist in equal amount for the odd-period quantum walk,however three cases including equal amount,unequal amount or even only one type may occur for the even-period quantum walk.
基金supported by grant DP3 DK104397,R01 EY024544,P30 EY010572 from the National Institutes of Health(Bethesda,MD)by unrestricted departmental funding from Research to Prevent Blindness(New York,NY)
文摘Age-related macular degeneration(AMD)has been classified in two groups,neovascular and non-neovascular,which historically has been synonymous with exudative and non-exudative,respectively.Neovascular AMD occurs when pathologic blood vessels,choroidal
基金supported in part by research grants from the National Institutes of Health(R01HL093140,R01EB009682,and R01DC010201)(RKW)the American Heart Association(0855733G)(RKW)the National Institute of Diabetes and Digestive and Kidney Diseases(5 U24 DK076169-04,Pilot and Feasibility Study 09MCG81)(TKB).
文摘Diabetic neuropathy(DN)is,at least in part,associated with the functional attenuation of vasa nervorum,the microvascular structure of peripheral nerves.Microvascular imaging options for vasa nervorum still remain limited.In this work,optical microangiography(OMAG),a volumetric,label-free imaging technique,is utilized for characterizing,with high resolution,blood perfusion of peripheral nerve in diabetic mice.We demonstrate that OMAG is able to visualize the structure of microvasculature and to quantify the changes of dynamic blood flow and vessel diameters during administration of vessel stimulant in both diabetic and normal mice.The results indicate the potential of OMAG to assess the blood supply of nerve involved in the pathology and treatment of DN.
文摘The cause of glaucoma,a disease defined by degeneration of retinal ganglion cells associated with cupping of the optic nerve head(ONH)and progressive vision loss,continues to be debated despite numerous advances in ophthalmic imaging and diagnostics.Although elevated intraocular pressure is often implicated,many studies,using a variety of imaging techniques including plain fundus photography,fluorescein angiography,laser Doppler flowmetry,and color Doppler ultrasound(1-4),have suggested that insufficiencies of ONH circulation may play a role in glaucoma pathogenesis.While all of these imaging modalities have been informative,each has a set of limitations,including low spatial resolution,invasiveness,restriction to superficial vessels,lack of repeatability,and modality specific artifacts.Optical coherence tomography angiography(OCTA),an imaging technology that can produce high resolution,three-dimensional images of fundus microcirculation,is well suited to overcome many of these limitations(5).
基金supported by the National Natural Science Foundation of China(Nos.11974032,11734001,and 11525414)the Key R&D Program of Guangdong Province(No.2018B030329001).
文摘Hybrid metal-dielectric structures combine the advantages of both metal and dielectric materials,enabling high-confined but low-loss magnetic and electric resonances through deliberate arrangements.However,their potential for enhancing magnetic emission has yet to be fully explored.Here,we study the magnetic and electric Purcell enhancement supported by a hybrid structure composed of a dielectric nanoring and a silver nanorod.This structure enables low Ohmic loss and highlyconfined field under the mode hybridization of magnetic resonances on a nanoring and electric resonances on a nanorod in the optical communication band.Thus,the 60-fold magnetic Purcell enhancement and 45-fold electric Purcell enhancement can be achieved.Over 90%of the radiation can be transmitted to the far field.For the sufficiently large Purcell enhancement,the position of emitter has a tolerance of several tens of nanometers,which brings convenience to experimental fabrications.Moreover,an array formed by this hybrid nanostructure can further enhance the magnetic Purcell factors.The system provides a feasible option to selectively excite magnetic and electric emission in integrated photonic circuits.It may also facilitate brighter magnetic emission sources and light-emitting metasurfaces with a more straightforward design.
