Evolution of the beam quality factor for various active medium positions within a Gaussian cavity

• Published in: Optics communications 2001-08, Vol.195 (5), p.315-325
• Main Authors: De Tomasi, F., Perrone, M.R., Protopapa, M.L.
• Format: Article
• Language: English
• Subjects: Beam characteristics: profile, intensity, and power; spatial pattern formation; Coherence; Exact sciences and technology; Excimer laser; Fundamental areas of phenomenology (including applications); Gas lasers including excimer and metal-vapor lasers; Laser optical systems: design and operation; Lasers; Optical resonators; Optics; Physics; Resonators, cavities, amplifiers, arrays, and rings
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/S0030-4018(01)01362-1

A 2-m-long plane-parallel cavity with a Gaussian reflectivity mirror has been applied to a XeCl discharge chamber with a 35-cm-long active medium and the temporal evolution of the main parameters of the intracavity laser radiation after reflection on the Gaussian mirror, has been analysed for various active medium positions within the cavity. It is shown that in cavities of equal length and effective Fresnel number, the properties of the intracavity radiation are dependent on the Gaussian mirror distance from the active medium, since the onset of laser action. Indeed, it has been found that the beam quality factor M 2 reaches smaller values by setting the Gaussian mirror closer to the active medium. It is also shown that a theory formerly developed for the evolution of the parameters of Schell–Gauss model beams propagating in Gaussian-mirror cavities provides a satisfactory description of experimental results.