Studies On The Manipulation Of The Optical Scattering Behavior Of Particles And Its Potential Applications

With the expectation that nano-optics require integrated devices to become increasingly miniaturized,artificial optical materials have become the frontier in this field.At present,artificial optical materials mainly include photonic crystals,metamaterials,metasurfaces and metalattices.They exhibit novel light manipulation phenomena which natural materials do not possess,and greatly expands people's cognition of materials.In-depth study of the factors that affect the light scattering behavior of micro-particles has unique theoretical value for realizing some novel optical phenomena and obtaining ultra-thin sub-wavelength optical structures.This is mainly due to the micro-particles are the basic unit constituting the artificial optical material,and its light scattering properties fundamentally modulate the optical phenomena.Researchers have discovered that the angular momentum channels of the opposite sign for light scattering of high-index media particles could behave almost independently,and subsequently designed sub-wavelength optical structures which were thinner than photonic crystals,metamaterials and metasurfaces.We intend to demonstrate its potential application in the construction of artificial optical materials by exploring new methods of light scattering based on angular momentum channels.Exploring the local scattering behavior of particles,in other words,the scattering behavior of the elementary particles that making up the artificial optical material,will provide additional degrees of freedom for manipulation of electromagnetic waves.We first focus on the light scattering behavior of an individual particle,and study the relationship between the light scattering characteristics of an individual particle and angular momentum channels in details.It is noted that the physical image of light interacting with particles is the interference of induced electric multipoles modes.Based on this concept,for the first time,an anomalous dipole-like mode in a linear dielectric rod array is recovered.Compared with the electric dipole mode,the distribution of the scattering field is quite similar,but the magnetic field distribution of the dipole-like mode satisfies the even symmetry,and the magnetic field distribution of the electric dipole mode is the odd symmetry.The rods with local scattering properties of singular dipoles modes are placed in a two-dimensional array to achieve 100% optical retro-reflection.Compared with the traditional methods of obtaining retroreflection with metamaterials,metasurfaces,this structure achieves the retro-reflection effect with in-plane property and CMOS compatibility at the same time.Next,we change the way to control the angular momentum channels,and all the angular momentum channels are aligned to the same resonant frequency.A scheme for establishing a three-channel near-degenerate resonance has been proposed by using homogeneous dielectric rods.In this case,the corresponding induced electric multipoles modes of all three channels are on the scattering resonance states,which greatly enhance the coupling between the rods.Then the induced multipole modes start to rotate,and they supplement the momentum of light waves in the lattice.Furthermore,we link the Dirac point in the photonic crystal with the circular multipoles modes in a single rod to achieve the purpose of steering the outing direction of light near the Dirac point,including the negative transmission and the positive transmission.The 0th and-1st transmittances quasi-periodically oscillate along with the increase of layer number.The circular multipole mode here is the microscopic representation of the Dirac point in the photonic crystal,and the Dirac point of the photonic crystal is a macroscopic proof of the circular multipoles modes.The phenomenon of retro-reflection based on the local scattering properties of dipole-like multipoles and the singular transmission of specific lattices with near degenerate resonances are both novel light scattering behaviors obtained by modulating the angular momentum channels of micro-particles.Here,the fundamental scattering effect of a unit particle in the entire structure has been fully presented.In addition,the configuration,lattice constant and other factors also play an auxiliary role in the modulation.Both retro-reflection and negative transmission structures have advantages such as low power consumption,easy fabrication and CMOS compatibility,and provide better alternative schemes for the development of Nano-optics.Retro-reflection forms an optical super lattice,which can be used in the field of atoms trapping and quantum switches.The singular transmission phenomenon can be used for beam splitting.Finally,exploring the microscopic correspondence of the overall lattice behavior could be a new research direction.