Phase-locked operation of a compact three slab-sections radio-frequency discharged CO2 laser

In order to obtain a compact source with a good power extraction and a low divergence we constructed a laser making use of both large area discharges and laser array principles. In this paper we show the near- and far-field patterns obtained from the laser working in unlocked and phase-locked conditions, and compare them to distributions obtained by means of simple diffraction theories. We give a modal description to the field distribution and discuss the conditions for the attainment of the phase-locked emission, making use of the information obtained from the spectrum of beat frequencies.