Abstract

The spectrally resolved profile of the unsaturated gain (PUG) of a cataphoretic HeCd⁺-Laser is determined for the first time with a new measuring method which uses the beat frequency spectrum of the axial laser modes. The different axial modes of a laser line move across the gain profile because of statistical variations of the resonator length. The laser modes are recorded as beat frequencies in the GHz region by a fast avalanche photodiode and a spectrum analyzer. Variable losses are inserted into the resonator by a pair of Brewster plates. The PUGs are deduced from the vanishing of the beat frequencies with increasing losses.

© 1992 IQEC