Nature CommunicationsUltrafast space-time optical merons in momentum-energy spaceMurat YessenovAhmed H. DorrahCheng GuoLayton A. HallJoon-Suh ParkJustin FreeEric G. JohnsonFederico CapassoShanhui FanAyman F. Abouraddy2025-09-29Full textDOI https://doi.org/10.1038/s41467-025-63641-6