Distributed Feedback Lasing with Cold Atoms

Alexander Schilke (1) , Claus Zimmermann (1) , Philippe W. Courteille (2) , William Guerin (1)

1 Physikalisches Institut [Tübingen]
2 IFSC-USP - Instituto de Física de São Carlos

There is currently a strong interest in mirrorless lasing. In these systems, the electromagnetic feedback is provided either by disorder, i.e., multiple scattering in the gain medium itself, or by order, i.e., multiple Bragg reflection. This corresponds, respectively, to ''random lasers" and ''photonic crystal lasers". The crossover regime, between order and disorder, or correlated disorder, starts also to be fruitfully investigated. Here, we report one-dimensional photonic crystal lasing, i.e., distributed feedback lasing, with a cold atom cloud that provides simultaneously both gain and feedback. The atoms are trapped in a 1D lattice, giving a density modulation that creates a strong Bragg reflection under a small angle of incidence. Pumping the atoms with auxiliary beams induces four wave mixing that provides gain. The combination of both ingredients generates a mirrorless laser with a conical output emission, whose apex angle is tunable with the lattice periodicity through the Bragg condition.

Domaines: Physique Atomique [physics.atom-ph]; Optique [physics.optics]

Alexander Schilke, Claus Zimmermann, Philippe W. Courteille, William Guerin. Distributed Feedback Lasing with Cold Atoms. 2011. ⟨hal-00626835v1⟩