A comparison between intensity noise spectra and also the line shapes of gain-guided, weakly-index-guided, and strongly-index-guided semiconductor lasers are made using numerical solution of Maxwell-Bloch equations in...A comparison between intensity noise spectra and also the line shapes of gain-guided, weakly-index-guided, and strongly-index-guided semiconductor lasers are made using numerical solution of Maxwell-Bloch equations including spontaneous emission noise.展开更多
In the fields of light manipulation and localization,quasiperiodic photonic crystals,or photonic quasicrystals[PQs],are causing an upsurge in research because of their rotational symmetry and long-range orientation of...In the fields of light manipulation and localization,quasiperiodic photonic crystals,or photonic quasicrystals[PQs],are causing an upsurge in research because of their rotational symmetry and long-range orientation of transverse lattice arrays,as they lack translational symmetry.It allows for the optimization of well-established light propagation properties and has introduced new guiding features.Therefore,as a class,quasiperiodic photonic crystal fibers,or photonic quasicrystal fibers[PQFs],are considered to add flexibility and richness to the optical properties of fibers and are expected to offer significant potential applications to optical fiber fields.In this review,the fundamental concept,working mechanisms,and invention history of PQFs are explained.Recent progress in optical property improvement and its novel applications in fields such as dispersion control,polarization-maintenance,supercontinuum generation,orbital angular momentum transmission,plasmon-based sensors and filters,and high nonlinearity and topological mode transmission,are then reviewed in detail.Bandgap-type air-guiding PQFs supporting low attenuation propagation and regulation of photonic density states of quasiperiodic cladding and in which light guidance is achieved by coherent Bragg scattering are also summarized.Finally,current challenges encountered in the guiding mechanisms and practical preparation techniques,as well as the prospects and research trends of PQFs,are also presented.展开更多
The mechanically guided assembly that relies on the compressive buckling of strate- gically patterned 2D thin films represents a robust route to complex 3D mesostructures in advanced materials and even functional micr...The mechanically guided assembly that relies on the compressive buckling of strate- gically patterned 2D thin films represents a robust route to complex 3D mesostructures in advanced materials and even functional micro-devices. Based on this approach, formation of complex 3D configurations with suspended curvy features or hierarchical geometries remains a challenge. In this paper, we incorporate the prestrained shape memory polymer in the 2D precur- sor design to enable local rolling deformations after the mechanical assembly through compressive buckling. A theoretical model captures quantitatively the effect of key design parameters on local rolling deformations. The combination of precisely controlled global buckling and local rolling expands substantially the range of accessible 3D configurations. The combined experimental and theoretical studies over a dozen of examples demonstrate the utility of the proposed strategy in achieving complex reprogrammable 3D mesostructures.展开更多
文摘A comparison between intensity noise spectra and also the line shapes of gain-guided, weakly-index-guided, and strongly-index-guided semiconductor lasers are made using numerical solution of Maxwell-Bloch equations including spontaneous emission noise.
基金supported by the Changsha Municipal Natural Science Foundation(No.kq2202295)the Scientific Research Foundation of Hunan Provincial Education Department(Nos.22B0273 and 21A0013)+1 种基金the National Natural Science Foundation of China(Nos.61405058 and 62075059)the Natural Science Foundation of Hunan Province(Nos.2017JJ2048 and 2020JJ4161)。
文摘In the fields of light manipulation and localization,quasiperiodic photonic crystals,or photonic quasicrystals[PQs],are causing an upsurge in research because of their rotational symmetry and long-range orientation of transverse lattice arrays,as they lack translational symmetry.It allows for the optimization of well-established light propagation properties and has introduced new guiding features.Therefore,as a class,quasiperiodic photonic crystal fibers,or photonic quasicrystal fibers[PQFs],are considered to add flexibility and richness to the optical properties of fibers and are expected to offer significant potential applications to optical fiber fields.In this review,the fundamental concept,working mechanisms,and invention history of PQFs are explained.Recent progress in optical property improvement and its novel applications in fields such as dispersion control,polarization-maintenance,supercontinuum generation,orbital angular momentum transmission,plasmon-based sensors and filters,and high nonlinearity and topological mode transmission,are then reviewed in detail.Bandgap-type air-guiding PQFs supporting low attenuation propagation and regulation of photonic density states of quasiperiodic cladding and in which light guidance is achieved by coherent Bragg scattering are also summarized.Finally,current challenges encountered in the guiding mechanisms and practical preparation techniques,as well as the prospects and research trends of PQFs,are also presented.
基金X.G. and Z.X. contributed equally to this work. Y.Z. acknowledges the support from the National Natural Science Foundation of China （Grant Nos. 11502129 and 11722217） and the Tsinghua National Laboratory for Information Science and Technology. Y.H. acknowledges the support from the NSF （Grant Nos. CMMI1400169, CMMI1534120 and CMMI1635443）. X.G. acknowledges the support from the National Natural Science Foundation of China （Grant Nos. 11702155）.
文摘The mechanically guided assembly that relies on the compressive buckling of strate- gically patterned 2D thin films represents a robust route to complex 3D mesostructures in advanced materials and even functional micro-devices. Based on this approach, formation of complex 3D configurations with suspended curvy features or hierarchical geometries remains a challenge. In this paper, we incorporate the prestrained shape memory polymer in the 2D precur- sor design to enable local rolling deformations after the mechanical assembly through compressive buckling. A theoretical model captures quantitatively the effect of key design parameters on local rolling deformations. The combination of precisely controlled global buckling and local rolling expands substantially the range of accessible 3D configurations. The combined experimental and theoretical studies over a dozen of examples demonstrate the utility of the proposed strategy in achieving complex reprogrammable 3D mesostructures.
