Superbunching from coherently driven atoms in a waveguide

We investigate the scattered field from $N$ identical two-level atoms resonantly driven by a weak coherent field in a one-dimensional waveguide. For atoms separated by the drive wavelength, increasing the number of atoms progressively suppresses transmission while enhancing photon bunching. Transmission becomes a superbunched $(N+1)$-photon scattering process that is predominantly incoherent. Remarkably, we find that this transmission is only possible through a process where all $N$ atoms are excited, enabling heralded multi-photon state generation with applications in long-distance entanglement and quantum metrology.