Backward, forward and around the corner lasing in air

We present common results on forward and backward lasing in atmospheric air via stimulated emission following multiphoton excitation of atomic species either present in air or created by dissociating the air molecular species. We show how we can achieve sideways lasing in air by focusing the UV pump beam with cylindrical lenses. Two-photon excited N atoms from previously dissociated molecular nitrogen provide lasing perpendicular to the UV pump laser. Extending to pumping with femtosecond lasers enables lasing from natural inert atomic species in air, eliminating the need for the dissociation step.