Published online by Cambridge University Press: 09 March 2009
The effects of finite bandwidth and random-phase pumping on parametric instabilities have been studied extensively (Thomson & Karush 1974; Thomson 1975; Laval et al. 1977). The possibilities arising from the use of this method and a time delay to obtain a spatial incoherence uniform illumination have been proven in experiments (Lehmberg & Obenschain 1983; Mima & Kato 1982; Kato & Mima 1982; Richardson 1981). In this paper we investigate this subject in an alternative way and obtain some results on the influence of the gain profile on parametric instabilities.