In recent years, Airy and vortex beams have drawn considerable attention in the field of optics due to their distinctive light field characteristics. Airy beams, with their non-diffracting propagation, self-healing capability, and parabolic self-accelerating trajectories [[1], [2], [3]], have found wide application in optical manipulation [[4], [5], [6]], surface plasmon control [7], and light-sheet microscopy [8]. Vortex beams, characterized by their helical phase fronts and annular intensity distributions [[9], [10], [11]], have shown immense research value in fields such as optical communication [12,13] and quantum technologies [14].Over the past decades, various methods have been developed for generating Airy and vortex beams. Airy beams, for instance, can be generated through active modulation using spatial light modulators (SLMs) [[15], [16], [17]], or via lens-based optical setups [18,19]. Similarly, vortex beams can be produced using phase plates that imprint specific phase profiles [20,21], or indirectly through nonlinear optical effects in dielectric media [22,23]. Despite their widespread use, these techniques often suffer from limited processing efficiency, high system integration complexity, and inadequate flexibility for dynamic modulation [24]. Metasurfaces, as a novel class of two-dimensional artificial electromagnetic materials, feature compact unit cells and subwavelength thickness [25,26], making them well-suited for integration with other devices [27], and thus a promising platform for light field modulation [28]. They have facilitated the advancement of various optical devices, including multifocal metalenses [29], multiband polarization converters [30], holographic imaging [31], wavefront mainpulation [32,53], and sensors [[33], [34], [35]]. Specifically, Reference [48] proposes an efficient genetic algorithm-assisted meta-atom optimization method for high-performance metasurface optics, enabling designers to create versatile, high-efficiency metasurface devices across a wide range of operating frequency bands. In the field of metalenses, Reference [49] presents a supersymmetric lens based on quadratic phase gradient transformation, which achieves two-dimensional spatial focus control. The use of encoded metasurface techniques further allows flexible multi-focus adjustment, with theoretical analysis and microwave experiments demonstrating strong consistency.In terms of polarization conversion, a dual-layer metamaterial design achieves nearly 100 % conversion efficiency in the 0.55–1.37 THz range, along with an in-depth analysis of the physical mechanisms and enhancement principles behind the polarization conversion [50]. Moreover, an innovative three-layer metallic metasurface structure is proposed to realize continuous polarization state modulation along arbitrary spatial trajectories, generating Bessel beams with longitudinal polarization control—expanding the potential of structured beams in applications such as optical encryption and biomedical imaging [51].Notably, the design of metasurfaces based on one-dimensional subwavelength gratings has demonstrated broad application potential in the terahertz regime, including sensing, light trapping, and nonlinear effects. The associated theoretical models and experimental approaches have also gradually matured [52]. Notably, metasurfaces offer precise control over both the amplitude and phase of electromagnetic waves, enabling new possibilities for the generation and manipulation of special beams. For example, in Ref. [37], dynamic modulation of the Airy beam was achieved by encoding a cubic phase distribution and two off-axis Fresnel lens phase profiles onto two cascaded metasurfaces, thereby broadening the applicability of Airy beams across various domains. Based on H-shaped metasurfaces [28] and silicon-based metasurfaces [36], broadband Airy beam generators were realized by rotating the orientation of unit cells to tailor the electromagnetic response in accordance with the Airy function. In Ref. [38], an electrically controlled encoded metasurface was employed to achieve dynamic tuning of the Airy beam; however, this method involves only phase modulation. Compared with Airy beams generated through simultaneous amplitude and phase modulation, such phase-only designs exhibit relatively weaker focusing and nondiffracting performance. Moreover, their functionalities remain largely singular.

The conductivity of photosensitive semiconductor materials exhibits an approximately quadratic relationship with incident light intensity, resulting in a smooth and continuous variation conducive to fine and precise control [46,47]. By adjusting parameters such as the intensity and spatial distribution of the pump light, accurate modulation of conductivity can be achieved, thereby enhancing the programmability and modulation flexibility of the metasurface. Leveraging this property, this work proposes a light-controlled programmable metasurface based on complex amplitude modulation to address the aforementioned challenges. Each metasurface unit comprises a patterned metallic layer embedded with photosensitive semiconductor material, a middle quartz spacer, and a metallic substrate. By adjusting the intensity of the pump light, the conductivity of the photosensitive silicon can be dynamically tuned, enabling control over the amplitude of co-polarized reflected light at 1.04 THz and 1.64 THz. Surface current distribution analysis further reveals the influence of silicon conductivity on the reflection amplitude. Additionally, by rotating the metasurface units around their geometric centers, a full 2π Pancharatnam–Berry (PB) phase modulation is achieved. Building on these principles, an optically controlled Airy beam generator capable of producing Airy beams with tunable parameters via conductivity modulation is designed. Furthermore, a multifunctional vector beam generator capable of dynamically switching between vortex beams at 1.04 THz and Airy beams at 1.64 THz has been developed to address the growing demand for versatile applications. This terahertz multifunctional beam generator shows great potential in biomedicine, particle manipulation, imaging, and detection.