Pancharatnam–Berry (PB) phase has become an effective tool to realize the photonic spin Hall effect (PSHE) in recent years, due to its capacity of enhancing the spin-orbit interaction. Various forms of PSHEs have bee...Pancharatnam–Berry (PB) phase has become an effective tool to realize the photonic spin Hall effect (PSHE) in recent years, due to its capacity of enhancing the spin-orbit interaction. Various forms of PSHEs have been proposed by tailoring the PB phase of light, however, the propagation trajectory control of the separated spin states has not been reported. In this paper, we realize the oscillated spin-dependent separation by using the well-designed PB phase optical elements based on the transverse-to-longitudinal mapping of Bessel beams. Two typical oscillated PSHEs, i.e., the spin states are circulated and reversed periodically, are experimentally demonstrated with two PB phase elements fabricated with liquid crystal. The displacements and periods of these oscillations can be controlled by changing the transverse vector of the input Bessel beam. The proposed method offers a new degree of freedom to manipulate the spin-dependent separation, and provides technical supports for the application in spin photonics.展开更多
The spin Hall effect of a light beam is essentially a product of circular birefringence but is rarely demonstrated.Here,we provide a scheme for initiating off-axis circular birefringence based on the spin-dependent wa...The spin Hall effect of a light beam is essentially a product of circular birefringence but is rarely demonstrated.Here,we provide a scheme for initiating off-axis circular birefringence based on the spin-dependent wave vector bifurcation of Bessel beams via a single liquid crystal Pancharatnam–Berry phase element.The tilted Bessel beam shows a detectable photonic spin Hall effect.By introducing the nonlinear propagation trajectories,the spin Hall effect is greatly enhanced.More surprisingly,the two spin states exactly propagate along the scaled trajectories,enabling flexible control of the spin separation.This phenomenon is also applicable to other Bessel-like beams with nonlinear trajectories,which have been already reported.展开更多
Based on the transverse-longitudinal mapping of Bessel beams,we propose a simple method to construct a self-similar Bessel-like beam whose transverse profile maintains a stretched form during propagation.Specifically,...Based on the transverse-longitudinal mapping of Bessel beams,we propose a simple method to construct a self-similar Bessel-like beam whose transverse profile maintains a stretched form during propagation.Specifically,the propagatingvariant width of this beam can be flexibly predesigned.We experimentally demonstrate three types of self-similar Bessellike beams whose width variations are linear,piecewise,and period functions of propagation distance,respectively.The experimental results match well with the theoretical predictions.We also demonstrate that our approach enables the generation of self-similar higher-order vortex Bessel-like beams.展开更多
Earth-abundant molybdenum disulfide(MoS_(2))shows a high application potential in thermoelectric(TE)field owing to its high Seebeck coefficient.However,the main obstacle to achieve high TE performance for the MoS_(2)m...Earth-abundant molybdenum disulfide(MoS_(2))shows a high application potential in thermoelectric(TE)field owing to its high Seebeck coefficient.However,the main obstacle to achieve high TE performance for the MoS_(2)material is its poor electrical conductivity.In this work,the flexible MoS_(2)/single-walled carbon nanotube(SWCNT)films with enhanced TE performance were fabricated via hydrothermal reaction,solution mixing,and subsequent vacuum filtration.The strong S-πinteraction and the energy filtering effect at the MoS_(2)/SWCNT interface produced an impressive power factor value of 107.99±4.98μW·m^(-1)·K^(-2)for the MoS_(2)/SWCNT composite films.In addition,the TE performance had high stability on bending deformation.Finally,at a temperature difference of 50 K,the assembled TE device of MoS_(2)/SWCNT films exhibited good output performance.This work provides a feasible reference to optimize the TE performance of MoS_(2)materials and demonstrates a high potential of flexible MoS_(2)-based composites in TE applications.展开更多
Pancharatnam-Berry(PB)phase elements are widely used for optical field modulation due to their precise control over beam amplitude and phase.However,conventional PB elements are inherently static,with fixed modulation...Pancharatnam-Berry(PB)phase elements are widely used for optical field modulation due to their precise control over beam amplitude and phase.However,conventional PB elements are inherently static,with fixed modulation functions post-fabrication,limiting their adaptability in complex application scenarios.In this paper,we propose a moiré-type PB element comprising two specially designed PB elements.The proposed element attaches the two spin states with rotation-dependent PB phases while preserving the spin,thereby enabling dynamic rotation-tunability of the PB phase.As a functional validation,we experimentally demonstrate the dynamic control over the rotation rate of the polarization-rotating beam.The moiré-type PB element was designed using the checker-board-phase encoding method and fabricated in liquid crystal via SD 1-based micro-lithography.A back-propagation correction is introduced to eliminate the diffraction effects caused by the element gap.An adjustable rotation rate of±240 deg/cm is achieved through±160 deg angular offset.Owing to its compact structure with high integration and operation simplicity,the moiré-type PB element offers a novel dynamic modulation solution for structured light field generation,particle manipulation,and advanced laser processing.展开更多
基金the National Key R&D Program of China(2017YFA0303800)the National Natural Science Foundations of China(NSFC)(12074312,11634010,12174309,12074313,11774289,91850118,and 11804277)+1 种基金Fundamental Research Funds for the Central Universities(3102019JC008)Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(CX202047).
文摘Pancharatnam–Berry (PB) phase has become an effective tool to realize the photonic spin Hall effect (PSHE) in recent years, due to its capacity of enhancing the spin-orbit interaction. Various forms of PSHEs have been proposed by tailoring the PB phase of light, however, the propagation trajectory control of the separated spin states has not been reported. In this paper, we realize the oscillated spin-dependent separation by using the well-designed PB phase optical elements based on the transverse-to-longitudinal mapping of Bessel beams. Two typical oscillated PSHEs, i.e., the spin states are circulated and reversed periodically, are experimentally demonstrated with two PB phase elements fabricated with liquid crystal. The displacements and periods of these oscillations can be controlled by changing the transverse vector of the input Bessel beam. The proposed method offers a new degree of freedom to manipulate the spin-dependent separation, and provides technical supports for the application in spin photonics.
基金National Key Research and Development Program of China(2022YFA1404800)National Natural Science Foundation of China(12074312,12174309,12074313)Fundamental Research Funds for the Central Universities(3102019JC008)。
文摘The spin Hall effect of a light beam is essentially a product of circular birefringence but is rarely demonstrated.Here,we provide a scheme for initiating off-axis circular birefringence based on the spin-dependent wave vector bifurcation of Bessel beams via a single liquid crystal Pancharatnam–Berry phase element.The tilted Bessel beam shows a detectable photonic spin Hall effect.By introducing the nonlinear propagation trajectories,the spin Hall effect is greatly enhanced.More surprisingly,the two spin states exactly propagate along the scaled trajectories,enabling flexible control of the spin separation.This phenomenon is also applicable to other Bessel-like beams with nonlinear trajectories,which have been already reported.
基金supported by the National Key Research and Development Program of China(No.2022YFA1404800)the National Natural Science Foundation of China(Nos.12074312,12174309,12074313,and 62175200)the Fundamental Research Funds for the Central Universities(No.3102019JC008)。
文摘Based on the transverse-longitudinal mapping of Bessel beams,we propose a simple method to construct a self-similar Bessel-like beam whose transverse profile maintains a stretched form during propagation.Specifically,the propagatingvariant width of this beam can be flexibly predesigned.We experimentally demonstrate three types of self-similar Bessellike beams whose width variations are linear,piecewise,and period functions of propagation distance,respectively.The experimental results match well with the theoretical predictions.We also demonstrate that our approach enables the generation of self-similar higher-order vortex Bessel-like beams.
基金financial support from the Natural Science Foundation of Chongqing,China(No.CSTB2023NSCQ-MSX0602)Fundamental Research Funds for the Central Universities(No.SWU-KR22041 and SWU-XDJH202314)+2 种基金the Science and Technology Innovation and Venture Capital Special Projects of TIANDI Science Technology Co.Ltd(No.2023-TD-ZD014-004 and 2023-TD-QN012)CCTEG Chongqing Research Institute(No.2023ZDYF19)Xinjiang Uygur Autonomous Region Colleges and Universities Basic Scientific Research Operating Expenses Scientific Research Projects(No.XJEDU2023P113).
文摘Earth-abundant molybdenum disulfide(MoS_(2))shows a high application potential in thermoelectric(TE)field owing to its high Seebeck coefficient.However,the main obstacle to achieve high TE performance for the MoS_(2)material is its poor electrical conductivity.In this work,the flexible MoS_(2)/single-walled carbon nanotube(SWCNT)films with enhanced TE performance were fabricated via hydrothermal reaction,solution mixing,and subsequent vacuum filtration.The strong S-πinteraction and the energy filtering effect at the MoS_(2)/SWCNT interface produced an impressive power factor value of 107.99±4.98μW·m^(-1)·K^(-2)for the MoS_(2)/SWCNT composite films.In addition,the TE performance had high stability on bending deformation.Finally,at a temperature difference of 50 K,the assembled TE device of MoS_(2)/SWCNT films exhibited good output performance.This work provides a feasible reference to optimize the TE performance of MoS_(2)materials and demonstrates a high potential of flexible MoS_(2)-based composites in TE applications.
基金National Key Research and Development Program of China(2022YFA1404800)National Natural Science Foundation of China(12474338,12474298,62305271,62175200,12374279,62475217)Fundamental Research Funds for the Central Universities(5110240015).
文摘Pancharatnam-Berry(PB)phase elements are widely used for optical field modulation due to their precise control over beam amplitude and phase.However,conventional PB elements are inherently static,with fixed modulation functions post-fabrication,limiting their adaptability in complex application scenarios.In this paper,we propose a moiré-type PB element comprising two specially designed PB elements.The proposed element attaches the two spin states with rotation-dependent PB phases while preserving the spin,thereby enabling dynamic rotation-tunability of the PB phase.As a functional validation,we experimentally demonstrate the dynamic control over the rotation rate of the polarization-rotating beam.The moiré-type PB element was designed using the checker-board-phase encoding method and fabricated in liquid crystal via SD 1-based micro-lithography.A back-propagation correction is introduced to eliminate the diffraction effects caused by the element gap.An adjustable rotation rate of±240 deg/cm is achieved through±160 deg angular offset.Owing to its compact structure with high integration and operation simplicity,the moiré-type PB element offers a novel dynamic modulation solution for structured light field generation,particle manipulation,and advanced laser processing.
