This work innovatively designs an all-dielectric metasurface fabricated using 3D printing technology with alumina as the substrate material. This metasurface successfully generates vectorial non-diffracting Bessel beams at a specific frequency of 0.1THz. Initially, through comprehensive simulation analysis of the interaction between the metasurface and the incident beam, it was discovered that the metasurface can precisely manipulate the properties of the transmitted beam based on the polarization state of the incident beam. Specifically, when illuminated by a left-handed circularly polarized (LCP) Gaussian beam, the transmitted beam manifests as a radially polarized Bessel beam. Conversely, under right-handed circularly polarized (RCP) Gaussian beam illumination, the transmitted light transforms into an azimuthally polarized Bessel beam. Building upon the theoretical simulations and considering experimental constraints, further experimental validation was conducted using linearly polarized light, confirming the effectiveness and feasibility of the proposed design. Experimental results demonstrate that the presented all-dielectric alumina metasurface, fabricated via 3D printing, successfully achieves the generation of vector nondiffracting Bessel beams. On one hand, the combination of alumina material and 3D printing technology significantly reduces manufacturing costs, laying a foundation for large scale application. On the other hand, leveraging the high precision of 3D printing ensures the accurate fabrication of the metasurface structure, thereby guaranteeing the high quality and stability of the generated vector beams. This work provides a novel approach for the efficient generation of Bessel beams and is expected to have profound implications in the field of terahertz technology.

Spectral broadening of light and generating new frequencies are among the most interesting aspects of nonlinear optics. Supercontinuum generation (SCG) is a especial nonlinear process that occurs when pulses with narrow linewidth or continuous-wave (CW) lightwaves experience huge spectral broadening. In this paper, for the first time, SCG in the terahertz (THz) and Infrared (IR) ranges in a designed silicon-based rib waveguide is simulated by solving the generalized nonlinear Schrödinger equation (GNLSE). To this end, we first design a silicon waveguide with a zero-dispersion wavelength (ZDW) in the THz region and then determine the linear and nonlinear parameters of the waveguide. Subsequently, IR to THz SCG is simulated by means of the split-step Fourier transform (SSFT), where the influences of different parameters such as input pulse width, pulse power and waveguide length are investigated. By launching a 60-fs, 10-kW hyperbolic secant pulse into a 6-mm waveguide, a 1.3-octave SCG is obtained.

In this paper, we report on the collinear spontaneous parametric down conversion (SPDC) with quantum theory in angle picture. Based on angle-dependent refractive index of biaxial crystal and the dielectric dispersion, we numerically simulate the effective nonlinear coefficients of BiB 3 O 6 (BIBO) crystal in principle planes. The results indicate that the most effective phase matching scheme is the type I in yz plane, while the secondary options are the type I, type II in xz plane. Considering the derivation of angular phase matching conditions, the calculation is convenient, and it is superior in determination of the spatial distribution of entangled photons.

In this paper, the optical properties of a nanoscale silicon slot-waveguide has been rigorously studied by using a full vectorial H-field finite element method (VFEM) based approach. The variations of effective indices, effective areas, power densities in the slot-region and the confinement factors of the slot waveguide are thoroughly investigated. The full vectorial magnetic and electric field profiles and Poynting vector (Sz) are also presented.

Microfiber loop resonator (MLR) and microfiber knot resonator (MKR) are fabricated using melt-stretching method for applications in temperature and current sensor, respectively. The MLR is embedded into low refractive index polymer for robustness. Although the spacing of the transmission comb spectrum of the MLR is unchanged with temperature, the extinction ratio of the spectrum is observed to decrease linearly with temperature due to induced changes in the material's refractive index. The slope of the extinction ratio reduction against temperature is about 0.043dB/°C. With the assistance of a copper wire that is wrapped by the MKR, resonant wavelength can be tuned by varying the electric current delivered to the wire. The resonant wavelength change is based on the thermally induced optical phase shift in the MKR due to the heat produced by the flow of electric current over a short transit length. It is shown that the wavelength shift is linearly proportional to the square of current in the copper wire with a tuning slope of 46 pm/A2.

Spin-polarization can be formed by the two components of soliton (electromagnetic wave) within the metallic waveguide. Under the resonant condition, the random transverse electric and magnetic fields of the solitons corresponding to the left-hand and right hand photons can be generated. Whenever a photon is absorbed by an object, an angular momentum of either +ℏ or -ℏ is imparted to the object, in which two possible spin states known as optoelectronic spins are exhibited. Furthermore, the array of optoelectronic spins, i.e., many particles can be generated and controlled by using the modified add-drop filter, in which the broad spectrum soliton can be generated and used to form large scale spin transport applications.

The optical properties of a two-level molecular system immersed in a thermal reservoir and irradiated by an electromagnetic field were studied using the optical stochastic Bloch equations. The effect of the solvent is modeled as a stochastical shift of the system's Bohr frequency and the electromagnetic field includes both pump and probe fields. The resulting analytical expressions were studied by means of two and three dimensional graphics of the optical properties as a function of the pump-frequency detuning factor and the strength of the noise source.

The impulsive excitation and phase-sensitive detection of coherent phonons enable the study of dynamical properties of the lattice. In pump-probe experiments with femtosecond time resolution the amplitude and phase of the coherent lattice motion can be detected with high sensitivity. Especially in semiconductors and semiconductor heterostructures, where a coherent phonon mode and free carriers are exited at the same time, important information about the carrier-phonon system far away from equilibrium is obtained. In bulk GaAs coherent plasmon-phonon modes can be traced via the associated macroscopic field. In GaAs-AlGaAs based heterostructures coupled phonon-intersubband plasmons, coupled Bloch-phonon oscillations, and coherent acoustic phonons are observed.

In this work a photorefractive effect in proton-exchanged planar waveguides on LiNbO 3 crystals is discussed. These waveguides are doped by copper with the aid of a new technique using the low-temperature ionic exchange. The experimental investigation has revealed the anomalous character of the photorefractive response in strongly doped waveguides. Photorefractive measurements are made over a wide range of H +, Cu + and Cu 2+ concentrations, altered by a seriesof oxidation treatments caused by back ionic exchange. Fabrication parameters allowing the realization of high photorefractive sensitivity either in visible or near infra-red ranges are identified.