•The ballistic trajectory of Airy-Gaussian-Vortex beam can be controlled by chiral parameter.•Competing mechanism of Airy term and Gaussian term is analyzed.•The overlap position of the center of Airy-Gaussian beam and optical vortex changes with different competing factors.•The situation of second-order counterrotating AiGV beam has been discussed.Based on the Huygens diffraction integral, the analytical expressions of electric field distribution of the Airy-Gaussian-Vortex (AiGV) beam in a chiral medium are derived, and its propagation properties are investigated. With increasing the value of chiral parameter γ, the parabolic deflection of the LCP light increases and the RCP light decreases respectively. For the first-order AiGV beam with only one positive or negative optical vortex (OV), a half-moon-shaped intensity profile can be observed because of overlap of the OV and the Airy main lobe, and then the main lobe will be reconstructed and the vortex could be recovered after the overlap position. The intensity distribution of AiGV beam, the deflection trajectories of central positions of Airy beam and OV under different competing parameters between Gaussian and Airy terms have been studied. Furthermore, for the second-order counterrotating AiGV beam with positive and negative vortexes, it could be considered the superposition of two first-order AiGV beams with respective positive and negative vortexes. Two vortexes can regenerate during propagation and the intensity distribution the AiGV beam in the far zone can be controlled by adjusting the coordinates of two vortexes.

•A novel simulation based optimization method is proposed for linear-k spectrometer.•The FWHM value of the PSF is used as the criterion for optimizing the spectrometer.•The k-linearity of spectrometer is assessed both theoretically and experimentally.•For real-time OCT image we employed the CUDA parallel computing technique. Nonlinear detection of the spectral interferograms in wavenumber (k) space degrades the depth-dependent signal sensitivity in conventional linear-in-λ spectrometer based spectral domain optical coherence tomography (SDOCT). Linear-k spectrometer enables high sensitivity SDOCT imaging without the need of resampling the digitized non-linear-in-k data. Here we report an effective optimization method for linear-k spectrometer used in a high-resolution SDOCT system. The design parameters of the linear-k spectrometer, including the material of the dispersive prism, the prism vertex angle, and the rotation angle between the grating and prism, are optimized through the numerical simulation of the spectral interference signal. As guided by the optimization results, we constructed the linear-k spectrometer based SDOCT system and evaluated its imaging performances. The axial resolution of the system can be maintained to be higher than 9.1μm throughout the imaging depth range of 2.42 mm. The sensitivity was experimentally measured to be 91 dB with −6 dB roll-off within the depth range of 1.2 mm.

•Refractive indices of NBT–xBT (x = 0, 0.06 and 0.08) single crystals were measured.•Sellmeier and single-oscillator dispersion equations of NBT–xBT crystals were obtained.•Refractive indices of NBT–xBT single crystals decrease with increasing BT content.Refractive indices of (1−x)Na0.5Bi0.5TiO3–xBaTiO3 (NBT–xBT, x = 0, 0.06 and 0.08) single crystals were measured at room temperature after poled along pseudo-cubic crystallographic direction [0 0 1]. The refractive indices decrease dramatically when the wavelength increases for all crystals. At the same wavelength, refractive indices of NBT–xBT single crystals decrease with increasing BT content. Sellmeier dispersion equations were obtained by least square fitting, which can be used to calculate the refractive indices in low absorption wavelength range. Parameters connected to the energy band structure were determined by fitting single-oscillator dispersion equation. Similar to most oxygen-octahedral ferroelectrics, NBT–xBT crystals have the same dispersion behavior described by the refractive-index dispersion parameter. Dispersion energies take on covalent crystal values.

We investigated theoretically the existence, stability and propagation dynamics of fundamental and dipole solitons in the potential featuring locally Gaussian modulation of linear refractive index and out-of-phase nonlinearity. Fundamental solitons are stable in the moderate power region and the stability window shrinks with the depth of nonlinearity modulation, while there exist several discrete narrow stable windows for the dipole solitons. Also, a power-dependent shape transformation is found in the high power region for deep enough nonlinear modulation. The transverse mobility of solitons launched with a tilt angle was also discussed, and the results show the critical tilt angles for soliton deflecting from the channel increase with a decrease of the propagation constant. For the low energy soliton, only part of the soliton would keep oscillating in the channel and the other part would deflect away even if the tilt angle is smaller than the critical value.

We present the properties of surface defect solitons at the interface between simple lattices and superlattices with spatially modulated nonlinearities. Numerical results reveal that for positive defects, surface defect solitons can only stably exist in low-power region of semi-infinite gap and are nonexistent in the first gap. While for the negative defects, surface defect solitons can stably exist in the moderate-power region of semi-infinite gap, but in the first gap, surface defect solitons are stable in the most of the whole existence region. The stability region of surface defect soliton narrows as the depth of modulation of nonlinearity increases regardless of defects.

Nonlinear phase shift and transmission experienced by a beam at the fundamental frequency during electro-optic modulated quasi-phase-matched second-harmonic generation are studied. Numerical results indicate that the nonlinear phase shift of fundamental wave shows a difference of π, while fundamental transmission is controllable only by applying a DC electric field along z-axis. The above effect can be implemented on high-contrast optical switching devices such as Mach–Zehnder push–pull device. The relationships between the characteristic (peak and dip) electric fields and the initial pump intensity are also discussed.