Recently, directed by Academician Zhuang Songlin, Professor Zhang Dawei from Future Optical Laboratory worked with his team members to make progress in metasurface generating and self-accelerating optical beams, contributing to innovations and findings in laser manufacture, optical storage, and biomedicine and many other areas.
Accelerating optical beams exhibit exotic features, such as nondiffractive propagation, self-acceleration, and self-healing. However, spatial light modulator-based generators of such beams suffer from narrow operational bandwidth, high cost, low diffraction efficiency, and limited integration capability. Although recent metasurface-based approaches have yielded generators with significantly improved bandwidth and integration capacities, the resultant devices usually have ultrashort working distances and limited control over characteristic beam parameters, which decreases their utility in optical imaging and manipulation applications. Professor Zhang’s team described a synthetic-phase metasurface-based approach that overcomes these problems and increases the degree of freedom to enable effective control of beam parameters by integrating a cubic phase profile and the phase of a Fresnel holographic lens into a single metasurface. The research achievements “All-Dielectric Synthetic-Phase Metasurfaces Generating Practical Airy Beams” were published in in international authoritative journal ACS Nano (IF: 14.588).
Conventional accelerating beam generators (such as spatial light modelators) are bulky and diffraction-inefficient, they also have a poorly resolved ability of phase manipulation that limits the accelerating beam’s minimum size and maximum degree of curvature. Professor Zhang Dawei’s team used a dielectric metasurface to generate highly focused nondiffractive Bessel-like accelerating beams with predefined arbitrary trajectories within a broadband spectral range of 550-710 nm. In particular, a similar metasurface with a combined phase profile allows the generation of a Bessel-like vortex beam with an ultrahigh numerical aperture of 0.79, resulting in a subwavelength beamwidth of 234nm (~0.43λ) down to the diffraction limit. This study promotes the diversity of Bessel-like accelerating beams for practical manipulation, optical storage, biomedical imaging, and material processing. The research achievements “Use of Dielectric Metasurfaces to Generate Deep-Subwavelength Nondiffractive Bessel-Like Beams with Arbitrary Trajectories and Ultralarge Deflection” were published in international top journal Laser & Photonics Reviews ( IF: 10.655).
Dr. Wen Jing and Chen Lei, a freshman of USST, finished the above two papers as the first author, with Professor Zhang Dawei and Professor Lei Dangyuan from City University of Hong Kong as the correspondent author.
Link to the papers: https://doi.org/10.1021/acsnano.0c07770, https://doi.org/10.1002/lpor.202000487