Characterization of excimer lasers for application to lenslet array homogenizers.
We investigate the best method of characterizing high-divergence lasers, such as excimer lasers, to suppress fine-scale intensity nonuniformity that is due to coherence effects of lenslet homogenizers. We show by a detailed analysis of the lenslet homogenizer that, for highest accuracy, a direct measurement of the value of the autocorrelation function should be made at the separation p of the lenslet elements, identified as the critical spatial period. We show that the commonly used characterization of lasers by the 1/e(2) width of the angular divergence is not the most accurate test and may overstate or understate the effectiveness of a given laser.
Lin
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Lawrence
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Buck
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