The 5th-generation mobile communication system (5G) has higher security requirements than previous systems. Accordingly, international standard organizations, operators, and equipment manufacturers are focusing extensively on 5G security technology. This paper analyzes the security requirements of 5G business applications, network architecture, the air interface, and user privacy. The development trends of 5G security architecture are summarized, with a focus on endogenous defense architecture, which represents a new trend in 5G security development. Several incremental 5G security technologies are reviewed, including physical layer security, lightweight encryption, network slice security, user privacy protection, and block chain technology applied to 5G.

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Based on the inverse Faraday effect, the light-induced magnetization field distributions are investigated for a 4π tight focusing configuration with azimuthally polarized beams. It is found that a superlong (16λ) magnetization chain, composed of 19 subwavelength (0.44λ) spherical spots with longitudinal magnetization field, can be achieved in the focal volume of the objective. Moreover, the magnetic force on a magnetic particle or particle trains produced by tightly focused azimuthally polarized beams are calculated and exploited for the stable trapping of magnetic particles. These unique focal field distributions may find potential applications in confocal microscopy, atom control, and magneto-optical data storage.

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