Narrow linewidth, tunable dye laser by multiple-prism beam expander
12 mJ, 10-Hz green pulses from frequency doubled Nd:YAG laser was used for pumping Rhodamine 6G in a dye laser based on multiple-prism beam expander. In order to increase the stability of the output pulse, a unique dye cell with variable dimensions of active medium was designed and constructed. By using multiple-prism dispersion theory, conditions for zero-dispersion in two and four-prism beam expander configuration was calculated. In the case of two-prism configuration, tuning range of dye laser was 565–595 nm and the linewidth of pulse at 580 nm was about 1.8 nm and it is in good agreement with the calculated amount of 1.6 nm. Furthermore, using four-prism configuration tuning range of 570–585 nm was measured and the linewidth of output pulse at 575 nm was reduced up to 0.33 nm. This value may be further improved up to 0.22 nm according these calculations. In this arrangement, creation of parasitic modes, aberration in two dimensions and most of the alignment problems with the lens telescopes were resolved.
KeywordsMultiple-prism dispersion Zero-dispersion Dye laser Linewidth
Authors would like to thank Dr. Khosro Madanipour for his technical assistance.
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