An external-cavity laser diode at 635 nm for laser display applications

We describe a diode laser system at 635 nm, which has been developed for a colour laser display. The poor beam quality of conventional high power lasers has lead to the conception that these lasers are not suited for laser displays. In this paper, we introduce a new laser system that eliminates some of the previous problems. The system is based on a broad area laser diode with external optical feedback, which improves the spatial coherence of the beam emitted from the diode. We investigate the operation of the laser system in connection with acousto-optic intensity modulation. A diffraction efficiency from 0th to 1st order of 92% and 60% is achieved for modulation rise times of 80 and 10 ns, respectively. The advantages of the feedback scheme are the ability to use compact diode lasers for display purposes while simultaneously obtaining fast rise times and high output power. The results demonstrate that the new red source is suitable for laser display applications.