en عمومى General پژوهشي Research This paper describes the passive Qswitch, based on polymer and organic dye BDN, of a pulsed Nd:YAG laser. Pulses of 27ns duration and peak power of 1.7MW for initial transmission of Q-switch 18.4% 0 T = have been obtained. We have obtained Q-switching efficiency of 77% for train of pulses of 31 and 76.2% 0 T = at the pump energy of 98J. We have also obtained the dependency of laser pulse characteristics on pump energy and initial transmission of Q-switch. We have obtained the damage threshold of this Q-switch at the pulse duration of 27ns to be13J cm2 . Dye, Nd:YAG laser, passive Qswitching, polymer. 27 32 http://ijop.ir/browse.php?a_code=A-10-159-1&slc_lang=en&sid=1 M. Dezhkam 10031947532846001159 10031947532846001159 Yes Department of Physics, University of Shiraz M. Soltanolkotabi 10031947532846001160 10031947532846001160 No Quantum Optics Group, Department of Physics, University of Isfahan