Continuous-wave laser without frequency-domain-mode structure: investigation of emission properties and buildup dynamics

Abstract

The development of a broadband cw laser with no Fabry–Perot-mode structure is detailed. Through insertion of frequency-selective elements a bandwidth of 12 GHz is achieved, resulting in a peak spectral power density of ~50 μW/MHz. With heterodyne techniques the broadband nature of the field is shown to result solely from fluctuations in the phase. A comparison between the output of the broadband laser and that of a conventional multimode laser demonstrates the different nature of the emission. Discrete lines in the rf intensity spectrum are examined with regard to their origin. The temporal evolution of the spectral profile, starting from quantum noise, is investigated. Several features of this system, which incorporates an intracavity acousto-optic modulator, are remarkably different from those of a conventional cw laser.