We investigate both analytically and numerically the propagation dynamic of on-axis and off-axis cosine-Gaussian (CG) beams in a linear medium with quadratic external potential. CG beam propagation evolves periodically with a period depended on the potential depth (α) and whether the beam shape is symmetrical with respect to optical axis. In each period, the CG beam first splits into two sub-beams with different accelerated direction; they then reverse the accelerated direction owing to the quadratic external potential and finally merge again to reproduce its initial shape, and the whole process repeats periodically. The intensity oscillation period of the off-axis CG beam is double times than that of the on-axis one. At the special position, the beam (or spectral) shape is strongly related to the initial spectral (beam) shape. The corresponding scaled relationship is that the spatial intensity I x (or spatial frequency axis k) is α times the spectral intensity I k (or space axis x). The interaction of two spatially separated CG beams still exhibit periodic evolution with complex structure in the regime of focal point. The propagation dynamics of two-dimensional CG beams are also presented. When the propagation distance is exactly an integer multiple of half period, there are four focal points in the diagonal position.

We investigate the process of dispersive waves (DWs) emitted from Gaussian pulse (GP) with an initial quadratic spectral phase (QSP). We show that the radiation of DWs is strongly affected by the QSP parameter. The conversion efficiency and resonant frequency of DWs are effectively enhanced and controlled by tuning the sign and magnitude of the initial QSP. At variance with the case of pure GP, the DWs emission is first advanced and then delayed for negatively QSP modulated GPs; while it is always delayed for positively QSP modulated GPs. We present a modified phase-matching formula that allows us to predict DWs spectral peaks. The resonant frequencies predicted by the phase-matching condition are in very good agreement with the results obtained from the numerical simulation based on the generalized nonlinear Schrödinger equation. The results presented here can be utilized as a effective tool to manipulate DWs emission for applications such as frequency conversion.

A polarized light sensor is applied to the front-end detection of a biomimetic polarized light navigation system, which is an important part of analyzing the atmospheric polarization mode and realizing biomimetic polarized light navigation, having received extensive attention in recent years. In this paper, biomimetic polarized light navigation in nature, the mechanism of polarized light navigation, point source sensor, imaging sensor, and a sensor based on micro nano machining technology are compared and analyzed, which provides a basis for the optimal selection of different polarized light sensors. The comparison results show that the point source sensor can be divided into basic point source sensor with simple structure and a point source sensor applied to integrated navigation. The imaging sensor can be divided into a simple time-sharing imaging sensor, a real-time amplitude splitting sensor that can detect images of multi-directional polarization angles, a real-time aperture splitting sensor that uses a light field camera, and a real-time focal plane light splitting sensor with high integration. In recent years, with the development of micro and nano machining technology, polarized light sensors are developing towards miniaturization and integration. In view of this, this paper also summarizes the latest progress of polarized light sensors based on micro and nano machining technology. Finally, this paper summarizes the possible future prospects and current challenges of polarized light sensor design, providing a reference for the feasibility selection of different polarized light sensors.

The dispersive waves (DWs) emitted from a Gaussian pulse with an initial sinusoidally spectral phase (SSP) modulation are investigated. By tailoring the modulation depth and frequency, the SSP results in complex pulses shape with a multipulses structure ranging from Airy‐like to pulse sequences having controllable delay and phase. These salient features are able to control and enhance the radiation frequency and energy conversion efficiency of the DWs. The resonant frequencies based on a modified phase‐matching condition are given, which agree with the numerical results obtained by solving the nonlinear Schrödinger equation directly. The results not only further extend the application of the pulse shaping technology in fiber optics, but also provide an alternative approach to manipulate the process of DWs emission which is relevant to the generation broadband supercontinuum as well as frequency comb.

In recent years, biomimetic polarization navigation has become a research hotspot in navigation fields because of its autonomy and concealment. Existing point-source polarization navigation sensors mainly use a logarithmic amplifier as the arithmetic unit to obtain polarization information. However, these sensors suffer from zero drift and low detection accuracy, which limits their application range. To address the above issues, a polarization navigation sensor based on a differential amplifier is designed as the operational unit. Based on the change of the arithmetic unit of the polarization signal, the algorithm for calculating the heading angle of the sensor is improved. The results of the orientation experiments with the designed sensor in clear weather indicate that the orientation error is ±1.243∘, and the standard deviation is 0.351°. The polarization navigation sensor can extract polarized light information and calculate the heading without accumulation of errors over time accurately and achieves good real-time performance.