Patent ID: 7830934
Filing Date: 2010-11-09
Classification: H01S

Abstract:
1. A method for controlling bandwidth in a multi-portion laser system comprising a first line narrowed oscillator laser system portion having a first gain generator providing a line narrowed seed pulse to a second gain generator laser system portion, wherein selection of a differential firing time between the generation of the seed pulse in the first laser system portion and the generation of the laser gain medium in the second laser system portion effects the bandwidth of a laser output light pulse from the multi-portion laser system, comprising: adjusting a target operating point as a function of a measured bandwidth and a target bandwidth; estimating a current operating point; adjusting the differential firing time as a function of the current operating point and the target operating point in order to drive the current operating point to the target operating point; and wherein the estimating a current operating point step comprises the use of a function which is readily computable or estimatable from an available measurement of a laser system operating parameter and which function also is monotonic with respect to differential firing time over the expected range of operation; the estimating of the current operating point step comprises utilizing the difference between a current differential firing time and a reference differential firing time; and dE/dt is estimated by applying a dither signal to the differential firing time and taking a respective ratio of the correlations of dither with laser output pulse energy and the actual differential firing time.