Since its invention, holography has emerged as a powerful tool to fully reconstruct the wavefronts of light including all the fundamental properties (amplitude, phase, polarization, wave vector, and frequency). For exploring the full capability for information storage/display and enhancing the encryption security of metasurface holograms, smart multiplexing techniques together with suitable metasurface designs are highly demanded. Here, we integrate multiple polarization manipulation channels for various spatial phase profiles into a single birefringent vectorial hologram by completely avoiding unwanted cross-talk. Multiple independent target phase profiles with quantified phase relations that can process significantly different information in different polarization states are realized within a single metasurface. For our metasurface holograms, we demonstrate high fidelity, large efficiency, broadband operation, and a total of twelve polarization channels. Such multichannel polarization multiplexing can be used for dynamic vectorial holographic display and can provide triple protection for optical security. The concept is appealing for applications of arbitrary spin to angular momentum conversion and various phase modulation/beam shaping elements.

We proposed combining temporally shaped (double-pulse train) laser pulses with spatially shaped (Bessel beam) laser pulses. By using a temporally shaped femtosecond laser Bessel-beam-assisted chemical etching method, the energy deposition efficiency was improved by adjusting the pulse delay to yield a stronger material modification and, thus, a higher etching depth. The etching depth was enhanced by a factor of 13 using the temporally shaped Bessel beam. The mechanism of etching depth enhancement was elucidated by localized transient-free electrons dynamics-induced structural and morphological changes. Micro-Raman spectroscopy was conducted to verify the structural changes inside the material. This method enables high-throughput, high-aspect-ratio microchannel fabrication in fused silica for potential applications in microfluidics.

Ultratrace molecular detections from a limited amount of highly diluted solutions can offer unprecedented benefits in the biomedical/analytical fields, such as in precancer diagnosis, forensic analysis, and food safety. However, huge difficulties exist in completely concentrating the target molecules within a sensitive area and thereby enhancing the detection sensitivity. Herein, we report the ultratrace molecular detection using a low-adhesive superhydrophobic surface-enhanced Raman spectroscopy (LAS-SERS) substrate fabricated by femtosecond laser ablation. The LAS-SERS substrate has good characteristics, including a contact angle as high as 154°, a contact angle hysteresis below 5°, and a simulated Raman signal enhancement factor of up to 6 × 10⁶. Compared to the previously developed superhydrophobic SERS (S-SERS) methods, the low-adhesive nature of the LAS-SERS method can greatly reduce the final contact area, thus significantly enhancing the detection limit. In our experiments, the final contact area of the LAS-SERS substrate was reduced by 19.5 times, corresponding to an 88.1 times increase in the concentration effect, as compared to the highly adhesive S-SERS substrates fabricated using the same technique. The enhanced condensation effect led to a detection limit as low as 10⁻¹⁴ M, which shows an obvious improvement compared to that of the other non-photolithography methods. The method reported herein offers a facile and efficient approach to the cost-effective fabrication of a high-performance LAS-SERS substrate for ultratrace molecular detection.

Bessel beams have attracted considerable interest because of their unique non‐diffractive, self‐healing characteristics. Different approaches have been proposed to generate Bessel beams, such as using axicons, diffractive optical elements, composite holograms, or spatial light modulators. However, these approaches have suffered from limited numerical aperture, low efficiency, polarization‐dependent properties, etc. Here, by utilizing dielectric Huygens metasurfaces as ultrathin, compact platforms by integrating the functionalities of Dammann gratings and axicons, we successfully demonstrate multiple Bessel beam generation with polarization‐independent property. The number of two‐dimensional arrays can be controlled flexibly, which can enhance information capacity with a total efficiency that can reach 66.36%. This method can have various applications, such as parallel laser fabrication, efficient optical tweezers, and optical communication.