Continuous Oscillation and Amplification in Light-Focusing Glass Lasers

A lenslike glass laser rod with a refractive index profile having a parabolic variation was developed for stable and continuous oscillation and amplification. This `SELFOC glass laser' had the following characteristics: 1) excellent optical transmission properties, as good as those of the optical waveguide known as SELFOC, 2) capability of oscillation in a clear single transverse mode, 3) high gain and high output power per unit volume and 4) a wide spectral width. Several characteristics of this laser are reported. A SELFOC laser rod 1.5 mm in diameter and about 100 mm long produced an output power of 3.5 W in multimode under an electrical exciation power of 3.83 kW. As a typical laser amplifier a gain of 0.1 dB/cm was obtained.