Harnessing spin and orbital angular momentum light for optimal algae growth.

The present study investigated the difference in transmittance of light carrying opposite spin angular momentum (SAM) and orbital angular momentum (OAM) through chlorella algal fluid with varying concentrations and thicknesses. Our results indicate that, under specific conditions, right-handed light sources exhibit higher transmittance in the algal fluid compared to left-handed light sources. Furthermore, we observed that light with OAM also demonstrated higher transmittance than other types of light sources, leading to faster cell density growth of Chlorella. Interestingly, we also discovered that light with OAM stimulates Chlorella to synthesize more proteins. These findings provide different insights for selecting appropriate light sources for large-scale algae cultivation, and may facilitate the realization of carbon peaking and carbon neutrality in the future.

Enhanced hair growth effects through low-level vortex beams radiation: An experimental animal study.

Photobiomodulation therapy (PBMT) is a non-invasive and pain-less treatment for hair loss. Researches on PBMT rarely considered the impact of different light structures. In this study, we irradiated shaven rats with both 650 nm, m = 32 vortex beams and ordinary Gaussian beams. The laser treatment was performed at 24-hour intervals for 20 days. The energy density was set to 4.25 J/cm2 . The results indicated that low-level vortex beam irradiation led to better stimulation of hair growth than the Gaussian beams, which might be related to deeper penetration. The underlying biological mechanisms are discussed in terms of the activation of Wnt/ß-catenin/sonic hedgehog pathway. Our results suggest that low-level vortex beam irradiation is advantageous to the treatment of hair loss because it is technically feasible, convenient and effective.