Broadening of the emission spectrum of a self-mode-locked laser

The emission spectrum of a self-mode-locked ruby laser was broadened by a plane-parallel glass plate to widths exceeding 6 cm^–1. The pulse duration was measured by the two-photon luminescence method and with an image-converter streak camera. It was established that the pulse duration was not affected by the broadening of the spectrum. This was explained by the finite relaxation time of the nonlinear absorber and was in agreement with the results of earlier investigation of the present authors.