Dynamic spatiotemporal beams that combine two independent and controllable orbital-angular-momenta using multiple optical-frequency-comb lines
Z. Zhao, H. Song, R. Zhang, K. Pang, C. Liu, H. Song, A. Almaiman, K. Manukyan, H. Zhou, B. Lynn, R. W. Boyd, M. Tur, and A. E. Willner, Nature Communications 11, 4099 (2020).